2025-11-19 @ CHESS 7b2

Final CHESS beam time of the 2025-3 run cycle.

Goals

• Ambient temperature data collection on new samples: R-state ATCase (Sarah), Insulin (Shaheer)
• Cryo data collection on Mac1, DNA
• Test T-jump data collection on Mac1, lysozyme
• Test serial data collection using prototype chip

Participants

Steve, Marcus, Sarah, Katie, Shaheer & Xiaokun.

Neglected to take our usual group photo, but Xiaokun snapped these of Katie & Sarah:

• 
  Katie and Sarah looping R-state ATCase crystals in the humid chamber

• 
  Katie and Sarah processing data at id7b2.

Data

Root directory at CHESS: /nfs/chess/raw/2025-3/id7b2/meisburger/20251119

Root directory on OSN: s3://diffuse-chess-public/20251119

Beamline setup

parameter	value	notes
X-ray energy	14 keV @ 0.01% bandwidth	Si 111 channel cut mono inserted
Beam size	100 µm x 100 µm	slit-defined, no CRL
Flux	6.86 x 10^10 ph/s	see CHESS nb #3 p. 61, ICol counts ~38,000 / 0.1 s
Background reduction	On-axis mirror with Mo tube, 600 µm ID	same prototype as 10/15 beamtime (no aperture glued on)
Centering camera	top-view and on-axis cameras	Top view: 1.713 µm / pixel at 4x zoom ratio; On axis: 0.740 µm / pixel at 4x zoom ratio
Beamstop	700 µm diameter Mo disk suspended on mylar sheet, semi-transparent	At this energy, the bleedthrough was more intense than usual, and there were some faint diffraction rings visible in the image
Data collection software	"MX Collect" (python) & SPEC	The main GUI was the same as last time, except that I added jump scan type for T-jump experiments, and transmission_factor key to the <prefix>_scan.json.
Temperature control	(various)	Collected at ambient temperature unless noted below

Steve arrived at ~10 am. John I and Tricia C set up the beamline. The flux is comparable to previous visits. Mike C was unable to glue the aperture on the Mo tube successfully, so we're using the on-axis system with an open tube again, similar to 10/15 beamtime. Interestingly, there is not scattering around the beamstop this time. I think the tube is somewhat misaligned with the beam, based on apparent ID according to X-ray scan, and this decreases the effective aperture of the tube.

• 
  Steve constructed a "sheet on sheet" (SOS) style serial chip using some double-sided tape, thick Kapton, a hole punch, and some 2.5 µm thick mylar film.

• 
  The SOS chip has two halves. A drop containing crystals is added to one mylar surface, and the other half is placed on top (no spacer). The static cling of the mylar is enough to hold the pieces in place.

• 
  The SOS chip mounted on the goniometer. The prototype scatter guard tube / on-axis viewing mirror is visible on the right.

Samples

Name	Sample	Well composition	Drop composition	Notes
Lysozyme	50 mg/mL lysozyme in 20 mM NaOAc pH 4.6	0.7-1.0 M NaCl, 0.1 M NaOAc pH 4.4	2 µL protein + 2 µL well solution	Shaheer's lysozyme tray (9/16/25).
Insulin	20 mg/mL bovine insulin in 20 mM Na2HPO4 10 mM EDTA	225-350 mM Na2HPO4/Na3PO4 (pH 10.0-10.6), 10 mM EDTA	4 µL protein solution + 4 µL well solution	Insulin tray #1 (11/6/2025). See Shaheer K Ando Lab notebook p. 17
ATCase	Escherichia coli Aspartate Transcarbamoylase and seed stock. 16 µM holoenzyme in 40 mM Tris pH 7.5, 15 mM MgCl2, 1 mM TCEP, 2 mM PALA	8% v/v Tacsimate pH 7.0, 5-15% PEG-3350	2 µL protein + 1 µL well solution + 1 µL seed stock	R-ATCase tray #1 (10/29/2025). See Sarah H Ando Lab notebook p. 103
Mac1	SARS CoV2 NSP3 macrodomain and seed stock from UCSF. 40 mg/mL Mac1 in 150 mM NaCl, 20 mM Tris pH 8, 5% glycerol	30% (w/vol) PEG 3000 + 100 mM CHES (pH 9.5)	2 µL protein + 1 µL well solution + 1 µL seeds (undiluted)	Mac1 tray #3 (11/13/2025). See Katie L Ando Lab notebook p. 20
DNA	S2T7-1, S2T7-2, and S2T7-3 single strands at 50 µM in 40 mM tris acetate, 2 mM EDTA	125 mM tris acetate, 37.5 mM Mg acetate, 1.75 M ammonium sulfate	6 µL DNA + 6 µL of 40 mM tris acetate, 25 mM Mg acetate, 1.17 M ammonium sulfate	DNA tray #1, "condition 2". See Steve Meisburger Ando Lab notebook #3, pp. 48, 49

• 
  Well D3 of Shaheer's lysozyme tray (9/16/2025) Well solution: ?? M NaCl, 0.1 M NaOAc pH = ??. Drop: 2 uL of lysozyme + 2 uL well solution

• 
  Well A1 of Insulin tray #1 (11/6/2025). Well solution: 225 mM Na₂HPO₄/Na₃PO₄ pH 10.0, 10 mM EDTA. Drop: 4 µL protein solution + 4 µL well solution.

• 
  Well A2 of Insulin tray #1 (11/6/2025). Well solution: 250 mM Na₂HPO₄/Na₃PO₄ pH 10.0, 10 mM EDTA. Drop: 4 µL protein solution + 4 µL well solution.

• 
  Well B1 of Mac1 tray #3 (11/13/25). Well solution: 30% (w/vol) PEG 3000 + 100 mM CHES (pH 9.5). Drop: 2 µl protein solution + 1 ul well solution + 1 ul seeds.

• 
  Well B2 of Mac1 tray #3 (11/13/25). Well solution: 30 (w/vol) PEG 3000 + 100 mM CHES (pH 9.5). Drop: 2 µl protein solution + 1 ul well solution + 1 ul seeds.

• 
  Well A1 of R-ATCase tray (10/29/25). Well solution: 8% v/v Tacsimate pH 7.0, 5% PEG-3350. Drop: 2 µL protein + 1 µL well solution + 1 µL seed stock.

• 
  Well A2 of R-ATCase tray (10/29/25). Well solution: 8% v/v Tacsimate pH 7.0, 7% PEG-3350. Drop: 2 µL protein + 1 µL well solution + 1 µL seed stock.

• 
  Well B1 of R-ATCase tray (10/29/25). Well solution: 8% v/v Tacsimate pH 7.0, 5% PEG-3350. Drop: 2 µL protein + 1 µL well solution + 1 µL seed stock.

• 
  Well B3 of R-ATCase tray (10/29/25). Well solution: 8% v/v Tacsimate pH 7.0, 9% PEG-3350. Drop: 2 µL protein + 1 µL well solution + 1 µL seed stock.

• 
  Well A5 of DNA tray #1 (9/19/25). Well solution: 125 mM tris acetate, 37.5 mM Mg acetate, 1.75 M ammonium sulfate. Drop: 6 µl DNA solution + 6 µl of 40 mM tris acetate, 25 mM Mg acetate, 1.17 M ammonium sulfate.

Data collection, day 1

1. Lysozyme

Marcus looped a lysozyme crystal in the humid chamber from well D3 of Shaheer's tray. He used a 400 µm loop and micro RT sleeve with 10 µL well solution in the tip.

Subdirectory: lysozyme/calibration_sample

Snapped images every 30˚: lys_1_30_30_oac_zoom1.png_{01..12}.png

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
lys_1_5374	0	360	0.1	3600	0.01	100	185	14
lys_1_bg_5375	0	360	1	360	0.1	100	185	14

Note

Because the meniscus was rather close to the sample, the background was taken through an empty part of the loop, rather than off the tip. There's some water scattering present.

xia2 processing

	lys_1_5374
Mosaic spread	0.014
Resolution	1.07
Unit Cell	[78.43, 78.43, 37.64, 90.0, 90.0, 90.0]
Image range	[1, 3600]
Completeness	96.7
Multiplicity	20.6
I/sigma	25.7
Rpim	0.013
Wilson B factor	16.26
Space group	P 43 21 2

2. Mac1, serial chip

Steve transferred a whole drop of Mac1 crystals (Katie's Mac1 Tray #3, well B1) to the SOS chip. First he pipetted some well solution onto the mylar film, and the scooped up the crystals with a micromesh. The crystals tend to clump together and move when the chip rotates, making it somewhat difficult to ensure that each crystal is exposed only once.

Subdirectory: mac1/serial/mac1_1

Took an image using the top-view camera: mac1_1_chip_tvc_zoom1.png

And another using the on-axis camera: mac1_1_oac_zoom1.png_1.png

Shot several well-isolated crystals (each line is a different crystal).

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1_1_5376	160	180	0.1	200	0.1	100	185	14
mac1_1_5377	160	180	0.1	200	0.1	100	185	14
mac1_1_5378	160	180	0.1	200	0.1	100	185	14
mac1_1_5379	160	180	0.1	200	0.1	100	185	14

The chip got caught on the guard aperture when rotating -- should make a smaller chip, or keep it vertical. Because crystals moved a lot, I'm not totally sure that I haven't hit the same crystal twice.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1_1_5380	205	225	0.1	200	0.1	100	185	14
mac1_1_5381	205	225	0.1	200	0.1	100	185	14
mac1_1_5382	205	225	0.1	200	0.1	100	185	14
mac1_1_5383	205	225	0.1	200	0.1	100	185	14
mac1_1_5384	205	225	0.1	200	0.1	100	185	14
mac1_1_5385	205	225	0.1	200	0.1	100	185	14
mac1_1_5386	205	225	0.1	200	0.1	100	185	14
mac1_1_5387	205	225	0.1	200	0.1	100	185	14
mac1_1_5388	205	225	0.1	200	0.1	100	185	14
mac1_1_5389	205	225	0.1	200	0.1	100	185	14

Note

5384 was close to its neighbors -- check for unindexed reflections. 5385 and 5388 were very close to the edge of the chip, is this an issue for background subtraction?

For background measurements, collect from a variety of locations near the crystals, including those with thick water layers, and locations with no liquid present.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1_1_bg_5390	205	225	1	20	1	100	185	14
mac1_1_bg_5391	205	225	1	20	1	100	185	14
mac1_1_bg_5392	205	225	1	20	1	100	185	14
mac1_1_bg_5393	205	225	1	20	1	100	185	14
mac1_1_bg_5394	205	225	1	20	1	100	185	14
mac1_1_bg_5395	205	225	1	20	1	100	185	14
mac1_1_bg_5396	205	225	1	20	1	100	185	14
mac1_1_bg_5397	205	225	1	20	1	100	185	14
mac1_1_bg_5398	205	225	1	20	1	100	185	14

Note

5391 is an air bubble? 5392 is through liquid near the chip edge.

Created an atlas image using the on-axis camera at zoom 1. The following SPEC command was used to translate the sample (6 x 6 grid):

ctrigger_auto; dmesh spinx -2.5 2.5 5 px -2.5 2.5 5 0.1

Saved images: /mac1/serial/mac1_1/atlas/mac1_1_atlas_oac_zoom1.png_{01..36}.png

xia2 processing

	mac1_1_5376	mac1_1_5377	mac1_1_5379	mac1_1_5380	mac1_1_5381	mac1_1_5382	mac1_1_5383	mac1_1_5384	mac1_1_5385	mac1_1_5386	mac1_1_5387	mac1_1_5388	mac1_1_5389	mac1_1_5378
Mosaic spread	0.013	0.02	0.024	0.017	0.02	0.033	0.023	0.025	0.028	0.021	0.024	0.023	0.084	1.043
Resolution	1.04	1.04	1.06	1.05	1.07	1.06	0.0	0.0	1.09	1.07	1.06	1.0	0.0	0.0
Unit Cell	[88.44, 88.44, 39.82, 90.0, 90.0, 90.0]	[88.44, 88.44, 39.84, 90.0, 90.0, 90.0]	[88.45, 88.45, 39.84, 90.0, 90.0, 90.0]	[88.43, 88.43, 39.79, 90.0, 90.0, 90.0]	[88.41, 88.41, 39.76, 90.0, 90.0, 90.0]	[88.38, 88.38, 39.67, 90.0, 90.0, 90.0]	[88.41, 88.41, 39.73, 90.0, 90.0, 90.0]	[88.41, 88.41, 39.74, 90.0, 90.0, 90.0]	[88.38, 88.38, 39.65, 90.0, 90.0, 90.0]	[88.44, 88.44, 39.81, 90.0, 90.0, 90.0]	[88.43, 88.43, 39.79, 90.0, 90.0, 90.0]	[88.41, 88.41, 39.72, 90.0, 90.0, 90.0]	[88.35, 88.35, 39.6, 90.0, 90.0, 90.0]	[91.57, 91.57, 44.97, 90.0, 90.0, 90.0]
Image range	[1, 200]	[1, 200]	[1, 200]	[1, 200]	[1, 200]	[1, 200]	[1, 200]	[1, 200]	[1, 200]	[1, 200]	[1, 200]	[1, 200]	[1, 200]	[1, 200]
Completeness	41.0	39.6	39.2	41.1	43.1	40.3	32.9	37.0	49.0	41.0	44.1	37.1	37.2	27.7
Multiplicity	1.3	1.3	1.4	1.3	1.3	1.4	1.4	1.3	1.2	1.4	1.3	1.3	1.3	1.7
I/sigma	8.0	6.7	5.8	8.8	7.2	10.8	6.6	5.9	12.4	7.0	5.7	10.8	7.0	0.2
Rpim	0.092	0.138	0.114	0.097	0.097	0.063	0.101	0.119	0.05	0.123	0.14	0.065	0.031	0.94
Wilson B factor	11.74	11.7	11.57	11.67	12.72	13.02	11.76	11.19	12.51	11.59	11.62	11.89	14.24	2.97
Space group	P 43	P 43	P 43	P 43	P 43	P 43	P 43	P 43	P 43	P 43	P 43	P 43	P 43	P 43

3. Insulin

Shaheer looped crystal from Insulin tray well A1 with 600 µm loop. Crystal size: 670 µm. Used sleeve with 8-9 µL well solution.

Subdirectory: Insulin/sk_A1

Saved a crystal image: sk_A1__1.png

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
sk_A1_5399	0	360	0.1	3600	0.01	100	190	14
sk_A1_bg_5400	0	360	1	360	0.1	100	190	14

4. ATCase

Sarah looped a crystal from the R-state ATCase tray #1, well B3 with a 200 µm loop. Used sleeve with 8 µL well solution.

Subdirectory: rstate_atcase

Saved a crystal image: b3_1_1.png

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
rstate_b3_1_5401	0	360	0.1	3600	0.01	47.1	300	14
rstate_b3_1_bg_5402	0	360	1	360	0.1	47.1	300	14

5. Insulin

Shaheer looped a crystal from Insulin Tray well A2. Loop size: 300 µm. Crystal size ~300 µm. Sleeve with 9 µL well solution.

Subdirectory: Insulin/sk_A2

Saved a crystal image: sk_A2__1.png

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
sk_A2_5403	0	360	0.1	3600	0.01	47.1	185	14
sk_A2_bg_5404	0	360	1	360	0.1	47.1	185	14

xia2 processing (all Insulin datasets)

	sk_A1_5399	sk_A2_5403
Mosaic spread	0.005	0.003
Resolution	1.15	1.18
Unit Cell	[78.25, 78.25, 78.25, 90.0, 90.0, 90.0]	[78.27, 78.27, 78.27, 90.0, 90.0, 90.0]
Image range	[1, 3600]	[1, 3600]
Completeness	98.6	100.0
Multiplicity	35.3	37.3
I/sigma	20.0	12.7
Rpim	0.014	0.02
Wilson B factor	18.04	18.72
Space group	I 2 3	I 2 3

6. ATCase

Katie looped a crystal from R-state Tray #1, well A1. Loop size: 200 µm; crystal size ~100 x 200 µm. Use sleeve with 9 µL well solution.

Subdirectory: rstate_atcase/a1_1

Saved a crystal image: a1_1__1.png

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
a1_1_5405	0	540	0.1	5400	0.01	28.6	300	14
a1_1_bg_5406	0	540	1	540	0.1	28.6	300	14

7. ATCase

Sarah looped a crystal from R-state tray #1, well A2. Loop size: 200 µm. Crystal size: 200 x 300 µm. Use sleeve with ~9 µL well solution.

Subdirectory: rstate_atcase/a2

Saved a crystal image: a2_1_1.png

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
a2_5407	0	540	0.1	5400	0.01	47.1	300	14
a2_bg_5408	0	540	1	540	0.1	47.1	300	14

8. ATCase

Sarah looped a hexagon-shaped crystal from R-state tray #1, well B1. Loop size: 150 µm. Crystal size: 150 µm. Use sleeve with 9 µL well solution.

Subdirectory: rstate_atcase/b1_1

Saved images every 30˚: b1_1__{01..12}.png

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
b1_1_5409	0	360	0.1	3600	0.01	36.7	300	14
b1_1_bg_5410	0	360	1	360	0.1	36.7	300	14

xia2 processing (all ATCase datasets above)

	rstate_b3_1_5401	a1_1_5405	b1_1_5409	a2_5407
Mosaic spread	0.037	0.025	0.021	0.078
Resolution	3.13	3.09	3.02	3.26
Unit Cell	[126.55, 152.08, 206.39, 90.0, 90.0, 90.0]	[126.54, 152.11, 206.54, 90.0, 90.0, 90.0]	[126.34, 152.58, 206.39, 90.0, 90.0, 90.0]	[126.46, 152.7, 206.5, 90.0, 90.0, 90.0]
Image range	[1, 3600]	[1, 5400]	[1, 3600]	[1, 5400]
Completeness	100.0	100.0	100.0	100.0
Multiplicity	13.9	20.8	13.9	20.6
I/sigma	4.3	3.1	4.3	5.7
Rpim	0.12	0.121	0.097	0.099
Wilson B factor	83.91	83.51	86.1	98.47
Space group	P 21 21 21	P 21 21 21	P 21 21 21	P 21 21 21

9. ATCase

Sarah looped another hexagon-looking crystal from well B1. Loop and crystal size: 150 µm. Same sleeve.

Subdirectory: rstate_atcase/b1_2

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
b1_2_5411	0	360	0.1	3600	0.01	47.1	300	14
b1_2_bg_5412	0	360	1	360	0.1	47.1	300	14

Warning

The beamstop was not in place during the b1_2_5411 and b1_2_bg_5412 data collections. It was quite far off, Steve had to re-align it using the periscope. Something must be loose in the mounting hardware.

10. Mac1 T-jump

Steve returned at 9:45 pm. The plan this evening is to attempt T-jump using Mac1 with paratone N.

The cold stream was placed end-on and chilled to 250 K. We'll jump down from ambient by unblocking the cold stream during data collection.

Steve looped a mac1 crystal from Katie's Mac1 Tray #3, well B2, in the humidity chamber. The crystal was then dipped in paratone N. The cold stream was blocked before mounting, and set to unblock at 5s into data collection (jump scan type).

Subdirectory: mac1/tjump/mac1_2

Saved 12 images: mac1_1_atlas_oac_zoom1.pngmac1_2_oac_zoom4_{01..12}.png (note: this is the actual file name, I made a mistake typing the prefix into the GUI text box)

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)	delay (s)	Tf (K)
mac1_2_jump250K_5422	0	360	0.1	3600	0.01	100	185	14	5	250
mac1_2_jump250K_bg_5423	0	360	1	360	0.1	100	185	14	5	250

The initial resolution is only ~1.7 Å. The oil is quite stressful for mac1 apparently.

xia2 processing

Processed 0-50 degree subset (before the T-jump) and 180-230 degrees (after the T-jump)

	mac1_2_jump250K_5422	mac1_2_jump250K_5422
Mosaic spread	0.141	0.215
Resolution	1.44	1.54
Unit Cell	[88.22, 88.22, 39.14, 90.0, 90.0, 90.0]	[88.95, 88.95, 39.13, 90.0, 90.0, 90.0]
Image range	[1, 500]	[1800, 2300]
Completeness	91.6	91.0
Multiplicity	2.1	2.1
I/sigma	9.5	6.7
Rpim	0.066	0.095
Wilson B factor	14.59	13.41
Space group	P 43	P 43

It's interesting that the Wilson B-factor seemed to decrease a bit even though the resolution and mosaicity are worse.

For fun, lets try blocking the cryostream (warm up to ambient) then jump down to 220 K. The cold steam cools at 360 K / hour, so it took a while to pre-cool the cold stream. This is not going to be a useful dataset -- mainly just to check whether ice forms or not.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)	delay (s)	Tf (K)
mac1_2_jump220K_5424	0	360	0.1	3600	0.01	100	185	14	5	220
mac1_2_jump220K_bg_5425	0	360	1	360	0.1	100	185	14	5	220

No ice.

Since mac1 doesn't tolerate oil very well, lets try lysozyme instead.

11. Lysozyme T-jump

Steve looped a lysozyme crystal from well C5 of Shaheer's tray, and dipped in paratone N. The cold stream is still at 220 K.

Subdirectory: lysozyme/tjump/lys_2

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)	delay (s)	Tf (K)
lys_2_jump220K_5426	0	360	0.1	3600	0.01	100	185	14	5	220

The diffraction resolution, again, was very bad. Ice rings showed up after cooling, but were only present in some frames, suggesting that it was surface ice, and not internal ice. Didn't bother with background on this one.

One of the piezo stages stopped moving, so we had to end data collection until it could be repaired.

Data collection, day 2

Keith and John were able to repair the piezo stage. The problem had something to do with the amplifier card. Thankfully, beamline 4B was not using theirs, and we were able to borrow it for the remainder of the run. Raley collected data during the day (for non-Diffuse Ando Lab beamtime) and Steve returned in the evening after she had finished.

The setup is similar to day 1, except Steve inserted the CRL, which focused the beam somewhat and increased the flux. Saved a beam picture using the on-axis camera and centering tool (YAG crystal): setup/beam_crl_oac_zoom4_1.png. These are the parameters that have changed since Day 1:

parameter	value	notes
Beam size	~40 µm x ~40 µm	CRL
Flux	1.37 x 10^11 ph/s	see CHESS nb #3 p. 63
Temperature control	cold stream from above, 100 K	standard cryo-MX config.

Back of the envelope dose calculation

The flux density is ~12x higher than with no CRL. The flux overall is ~30x lower than with the multilayer mono (i.e. standard cryo-MX). For low dose cryo, we usually operate with 20% transmission and collect for ~30 s. This suggests I should be using about 6x longer exposure times than usual, collecting 3-5 minutes per sample.

The plan is to collect cryo datasets from Mac1 and DNA.

12. Mac1 100K

Steve looped a mac1 crystal from well B1 of Katie's Mac1 Tray #3, to test whether it vitrifies without adding cryoprotectants. Worked in the humidity chamber, and used a sleeve with well solution to transport the sample into the hutch. The sleeve was removed before placing the sample on the goniometer (cold stream blocked using a credit card). The stream was unblocked quickly to freeze the sample.

Subdirectory: mac1/cryo/mac1_3

Snapped images every 30˚: mac1_3_100K_oac_zoom4_{01..12}.png

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1_3_100K_5478	0	360	0.1	3600	0.06	100	185	14
mac1_3_100K_bg_5479	0	360	1	360	0.6	100	185	14

The diffraction resolution looks good, except that it appears anisotropic. The end-on view (~90 degrees) is streaky and lower resolution. The spots are fuzzy looking too.

13. Mac1 100K

Looped another from the same well.

Subdirectory: mac1/cryo/mac1_4

Snapped images every 30˚: mac1_4_100K_oac_zoom4_{01..12}.png

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
snap_5480	335		0.1	1	0.1	100	185	14
mac1_4_100K_5481	0	360	0.1	3600	0.06	100	185	14

This appears to be a bit lower resolution than the last one.

xia2 processing (both mac1 cryo datasets)

	mac1_3_100K_5478	mac1_4_100K_5481
Mosaic spread	0.16	0.255
Resolution	1.0	1.07
Unit Cell	[87.83, 87.83, 38.95, 90.0, 90.0, 90.0]	[87.39, 87.39, 38.39, 90.0, 90.0, 90.0]
Image range	[1, 3600]	[1, 3600]
Completeness	80.3	94.1
Multiplicity	10.5	10.6
I/sigma	10.4	4.3
Rpim	0.021	0.042
Wilson B factor	11.18	10.86
Space group	P 43	P 43

14. DNA 100K

Steve looped several DNA crystals from DNA tray #1, well A5. Freezing the DNA crystals directly in mother liquor did not work -- there was too much ice.

Steve mixed up a solution of ethylene glycol and well solution in a 1:1 ratio, and made a drop on the coverslip. After looping a crystal, he quickly dipped it in the cryo solution, then placed the loop within a sleeve for transport to the hutch.

Subdirectory: dna/cryo/dna_1

Snapped images every 30˚: dna_1_100K_oac_zoom4_{01..12}.png

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
dna_1_100K_5486	0	360	0.1	3600	0.06	100	185	14
dna_1_100K_bg_5487	0	360	1	360	0.6	100	185	14
dna_1_100K_5488	20		0	1	10	100	185	14
dna_1_100K_bg_5489	20		0	1	10	100	185	14

Note

5488 and 5489 are long exposures (no rotation). I was curious what features are visible at high resolution, if any. This may require background subtraction to properly visualize.

15. DNA 100K

Looped another. This is quite a large crystal, but it's sitting on a loop with a big gob of cryo hanging off the bottom. Background subtraction will be tricky.

Subdirectory: dna/cryo/dna_2

Snapped images every 30˚: dna_2_100K_oac_zoom4_{01..12}.png

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
collect_5498	0	360	0.1	3600	0.06	100	185	14
dna_2_100K_bg_5499	0	360	1	360	0.6	100	185	14

Note

The first sample should be named dna_2_100K_5498. I forgot to change the prefix after restarting the software.

Next, take a shot through the gob of ethylene glycol (EG) cryo solution hanging off the bottom of the loop, and again off the tip of the loop. This might be useful for background corrections.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
eg_100K_5500	210		0	1	0.6	100	185	14
eg_100K_bg_5501	210		0	1	0.6	100	185	14

xia2 processing (both DNA datasets)

	dna_1_100K_5486	collect_5498
Mosaic spread	0.208	0.168
Resolution	4.21	4.0
Unit Cell	[104.91, 104.91, 91.02, 90.0, 90.0, 120.0]	[104.6, 104.6, 93.6, 90.0, 90.0, 120.0]
Image range	[1, 3600]	[1, 3600]
Completeness	100.0	100.0
Multiplicity	10.5	10.6
I/sigma	14.3	23.5
Rpim	0.015	0.01
Wilson B factor	251.25	233.38
Space group	R 3	R 3

Declaring victory. Done for 2025.

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