2026-03-25 @ CHESS 7b2

Final CHESS beam time of the 2026-1 run cycle.

Goals

Demonstrate data collection and processing procedures for Prophet Town
- Will develop automations for data & metadata ingestion into the diffuse hub
Screen initial DHFR hits
- Develop a procedure to collect data in the dark, keeping samples at 4˚ C.
- Did we successfully reproduce the P2₁2₁2₁ crystal forms with folate +/- NADP?
Screen Mac1 C2 crystals grown in microbatch
- Are the unit cells more consistent, compared with vapor diffusion?

Participants

Steve M, Katie L, & Xiaokun P from Ando lab; Joseph L from Radial; Michael A from Prophet Town; support from John I & Tricia C at CHESS

Data

Root directory at CHESS: /nfs/chess/raw/2026-1/id7b2/meisburger/20260325

Root directory on OSN: s3://diffuse-chess-public/20260325

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 (initially)	Slit-defined, no CRL. Adjusted to match crystal size when noted, below.
Flux	3.96 x 10¹⁰ ph/s	See CHESS 7b2 beamline notebook #3
Background reduction	On-axis mirror with Mo tube only (no aperture)
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 produces faint diffraction rings.
Data collection software	"MX Collect" (python) & SPEC	No changes since last time
Temperature control	none (initially)	For DHFR only, the Oxford cryostream was installed end-on and set to 277 K

DHFR samples were looped in the Ando Lab cold room under red light and transported to CHESS in a cold block (diversified biotech).
Setup for collecting data from DHFR at 277 K, with amber light source for centering.

Steve arrived at noon. The station alignment was delayed by an accelerator access, but was completed by 1:30. Steve added shielding to reduce background shadows in the image (lead tape upstream of the aperture, steel plate leaning against the back side of the tower). He also adjusted the camera lighting.

Samples

The following samples were grown in 24-well hanging-drop vapor diffusion trays:

Name	Sample	Well composition	Drop composition	Notes
Mac1 (P4₃ space group)	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 (2/10/2026). See Katie L Ando Lab notebook p. 32
Lysozyme	Hen egg lysozyme, 50 mg/mL in NaOAc	0.6 M NaCl, 100 mM NaOAc pH 4.2	2 µL protein + 2 µL well solution	Min P's practice tray, dated 10/17/2025.
DHFR-Folate	E. coli dihydrofolate reductase expressed and purified at Cornell. Dialyzed in 20 mM imidazole pH 7.0 with 1 mM folic acid and concentrated to 35 mg/mL	15% PEG 6000, 300 mM MnCl₂, 50 mM Cacodylate pH 7.0	1 µL protein + 1 µL well solution, streak seeded after equilibration	DHFR Tray #2 (3/6/2026). All procedures under red light at 4˚C. See Steve's Ando Lab Notebook #3, pp. 60, 64, 66, 69, 70
DHFR-Folate-NADP	E. coli dihydrofolate reductase expressed and purified at Cornell. Dialyzed in 20 mM imidazole pH 7.0 with 1 mM folic acid and concentrated to 35 mg/mL. NADP+ added in 3:1 molar excess (final concentrations: 31.5 mg/mL DHFR, 6.3 mM NADP)	20% PEG 400, 100 mM CaCl₂, 40 mM MES pH 6.5	1 µL protein + 1 µL well solution, streak seeded after equilibration	DHFR Tray #1 row C (3/14/202). All procedures under red light at 4˚C. See Steve's Ando Lab Notebook #3, pp. 67, 68, 70

The Mac1 C2 crystals were grown in 24 sitting well trays under paraffin oil (microbatch method):

Name	Sample	Precipitant	Drop composition	Notes
Mac1 (C2 space group)	SARS CoV2 NSP3 macrodomain "C2" construct expressed and purified at Cornell. In 150 mM NaCl, 20 mM Tris pH 8, 5% glycerol, 2 mM DTT, concentrated to 31 mg/mL	16-18% PEG 4000, 20 mM NaOAc, 20 mM Tris pH 8.5	Row B: 2 µL protein + 2 µL precipitant + 0.5 µL seed stock; Row C: 4 µL protein + 4 µL precipitant solutions + 0.5 µL seed stock	Mac1 C2 microbatch tray dated 3/3/2026 (row B) and 3/12/2025 (row C). See Katie L Ando Lab notebook pp. 37, 40, 41

Mac1 crystal mounted on the beamline, from Katie L's tray dated 2/10/2026. Well solution: 30% PEG 3000, 100 mM CHES pH 9.5. Drop: 2 µL protein + 1 µL well solution + 1 µL seed stock.
Lysozyme crystal mounted on the beamline, from well A1 of Min P's practice tray, dated 10/17/2025. Well solution: 0.6 M NaCl, 100 mM NaOAc pH 4.2. Drop: 2 µL protein + 2 µL well solution
Mac1 crystals (C2 form) from Katie L's microbatch under oil tray, third row (C) dated 3/12/2026. Precipitant solution: 18% PEG 4000, 20 mM NaOAc, 20 mM Tris pH 8.5. Drops contain 4 µL protein + 4 µL precipitant solutions + 0.5 µL seed stock (undiluted) under paraffin oil.
Mac1 crystals (C2 form) mounted on the beamline, from Katie L's microbatch under oil tray, second row (B) dated 3/3/2026. Precipitant solution: 16% PEG 4000, 20 mM NaOAc, 20 mM Tris pH 8.5. Drops contain 2 µL protein + 2 µL precipitant solutions + 0.5 µL seed stock (undiluted) under paraffin oil.
DHFR-Folate crystals from well D2 of Steve's DHFR Tray #2, dated 3/6/2026. Well solution: 15% PEG 6000, 300 mM MnCl2, 50 mM Cacodylate pH 7.0. Drop: 1 µL protein + 1 µL well solution, streak seeded on 3/14/2026.
DHFR-Folate-NADP crystals mounted on the beamline, from well C4 of Steve's DHFR Tray #1 dated 3/14/2026. Well solution: 20% PEG 400, 100 mM CaCl₂, 40 mM MES pH 6.5. Drop: 1 µL protein + 1 µL well solution, streak seeded on 3/20/2026.

Data collection

1. Mac1 (P4₃)

Xiokun looped a mac1 crystal from Katie's tray dated 2/10/2026, well B2. Crystal is a bit larger than 200 µm.

Subdirectory: mac1/mac1_1

Snapped images every 30˚ using the on-axis camera, prefix: mac1_1_oac_zoom4.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1_1_4796	0	360	0.1	3600	0.02	100	185	13.99
mac1_1_bg_4797	0	360	1	360	0.2	100	185	13.99

xia2 processing

	mac1_1_4796
Mosaic spread	0.007
Resolution	1.05
Unit Cell	[89.2, 89.2, 40.23, 90.0, 90.0, 90.0]
Image range	[1, 3600]
Completeness	87.9
Multiplicity	11.3
I/sigma	19.7
Rpim	0.014
Wilson B factor	13.28
Space group	P 43

2. Lysozyme

Xiaokun looped a lysozyme crystal from MJP tray dated 10/17/2025 well A1 using a 600 µm loop.

Subdirectory: lysozyme/lys_1

Snapped images every 30˚ using the on-axis camera, prefix: lys_1_oac_zoom1

Vector scan over ~600 µm distance.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
lys_1_4798	0	720	0.1	7200	0.05	100	185	13.99
lys_1_bg_4799	0	360	1	360	0.5	100	185	13.99

xia2 processing

Ran xia2 on the first 360 degrees, and the entire 720 degrees.

	lys_1_4798	lys_1_4798
Mosaic spread	0.027	0.031
Resolution	1.1	1.09
Unit Cell	[79.11, 79.11, 38.03, 90.0, 90.0, 90.0]	[79.11, 79.11, 38.04, 90.0, 90.0, 90.0]
Image range	[1, 3600]	[1, 7200]
Completeness	100.0	100.0
Multiplicity	21.4	42.0
I/sigma	31.5	40.5
Rpim	0.007	0.005
Wilson B factor	17.88	18.18
Space group	P 43 21 2	P 43 21 2

3. Mac1 (P4₃)

Steve bent a 200 µm loop to better orient mac1 relative to the rotation axis. Xiaokun looped another mac1 crystal from the same drop (Katie's tray dated 2026/2/10, well B2). The crystal is ~200 µm in diameter, and ~50 µm in the other dimension.

Subdirectory: mac1/mac1_2

Snapped images every 30˚ using the on-axis camera, prefix: mac1_2_oac_zoom4.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1_2_4800	0	360	0.1	3600	0.02	100	185	13.99
mac1_2_bg_4801	0	360	1	360	0.2	100	185	13.99

xia2 processing

	mac1_2_4800
Mosaic spread	0.006
Resolution	1.09
Unit Cell	[89.21, 89.21, 40.25, 90.0, 90.0, 90.0]
Image range	[1, 3600]
Completeness	98.6
Multiplicity	11.1
I/sigma	14.7
Rpim	0.019
Wilson B factor	13.41
Space group	P 43

4. Mac1 (P4₃)

Xiaokun looped another mac1 crystal from the same drop (Katie's tray dated 2026/2/10, well B2). A bit larger than the ~200 µm loop, and ~100 µm thick. The crystal is covered by a thick PEG skin, and not clearly visibile in the centering camera.

Subdirectory: mac1/mac1_3

Snapped images every 30˚ using the on-axis camera, prefix: mac1_3_oac_zoom4.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1_3_4802	0	360	0.1	3600	0.02	100	185	13.99

xia2 processing

	mac1_3_4802
Mosaic spread	0.005
Resolution	1.08
Unit Cell	[89.26, 89.26, 40.35, 90.0, 90.0, 90.0]
Image range	[1, 3600]
Completeness	93.5
Multiplicity	11.5
I/sigma	13.3
Rpim	0.022
Wilson B factor	13.16
Space group	P 43

multiple lattices

Unusable for diffuse (50% indexing rate). Evidently there are two crystals in the loop. Background skipped.

beam tuneup

Steve tuned up the beam again. The flux has dropped somewhat: 3 x 10¹⁰ ph/s in 100 x 100 µm beam.

5. Mac1 (C2)

Xiaokun looped a mac1 crystal (C2 form) from microbatch tray well C1. NVH oil was used to disperse the crystals before looping. A crystal of approx. 200 µm x 20 µm was mounted using a 50 x 500 µm inclined loop.

Subdirectory: mac1_C2/mac1c2_1

Snapped images every 30˚ using the on-axis camera. The first set of camera images were accidentally named mac1c2_1_oac_zoom4, the actual zoom ratio was 1x. Took another set using 4x zoom named mac1c2_1_oac_2_zoom4

Beam size changed to 50 x 50 µm.

Vector scan.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1c2_1_4803	180	540	0.1	3600	0.02	100	185	13.99
mac1c2_1_4804	180	540	1	360	0.2	100	185	13.99

multiple lattices

Possibly multiple crystals. Xia2 result: 30.7% indexed, unit cell 135.86, 30.74, 38.59 90, 100.64, 90. Mosaicity 0.0698. Difference between calculated & observed centroids is faily small & stable from phi=180˚-380˚, then got really bad at the end.

6. Mac1 (C2)

Katie looped mac1 crystal (C2 form) from the same tray, well B1 with a 30 x 300 µm EV loop. The crystal was chunky, ~100 x 600 µm. Collected data from the bottom, middle, and end.

Subdirectory: mac1_C2/mac1c2_2

Snapped images every 30˚ using the on-axis camera, prefix: mac1c2_2_oac_zoom2.

Beam size changed to 100 x 100 µm.

prefix	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1c2_2_bottom_4805	180	0.1	1800	0.01	100	185	13.99
mac1c2_2_middle_4806	180	0.1	1800	0.01	100	185	13.99
mac1c2_2_end_4807	180	0.1	1800	0.01	100	185	13.99

multiple lattices

By eye, the bottom dataset was less 'twinned', although all had low indexing percentages.

7. Mac1 (C2)

Katie picked up a smaller bundle (200 µm x 50 µm) from well B1 using a 50 x 500 µm included microloop E.

Subdirectory: mac1_C2/mac1c2_3

Snapped images every 30˚ using the on-axis camera, prefix: mac1c2_3_oac_zoom2.

Beam size changed to 50 x 50 µm.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1c2_3_4808	120	300	0.1	1800	0.02	100	185	13.99

xia2 processing

	mac1c2_3_4808
Mosaic spread	0.393
Resolution	1.85
Unit Cell	[135.52, 30.62, 38.09, 90.0, 98.71, 90.0]
Image range	[1, 1800]
Completeness	99.0
Multiplicity	3.4
I/sigma	4.6
Rpim	0.101
Wilson B factor	20.23
Space group	C 1 2 1

multiple lattices

Weak diffraction, but seems to be two lattices.

8. Mac1 (C2)

Steve scooped up a whole mess of mac1 crystals (C2 form) from well C1 using a micromesh.

Strategy: collect small wedges of data from isolated crystals using a small beam.

Beam size changed to 30 x 30 µm.

Subdirectory: mac1_C2/mac1c2_4

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1c2_3_4809	50	140	0.1	900	0.08	100	185	13.99

file name error

The prefix should have been mac1c2_4_4809 (sample 4 instead of 3).

Continue with other crystals on this mount.

Note

I made the dubious decision to create new directory for each crystal. Previously, when collecting from serial chips, I put all the datasets in the same subdirectory named after the mount (chip_L1, etc).

Subdirectory: mac1_C2/mac1c2_5

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1c2_5_4810	50	140	0.1	900	0.08	100	185	13.99

Subdirectory: mac1_C2/mac1c2_6

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1c2_6_4811	50	140	0.1	900	0.08	100	185	13.99

Subdirectory: mac1_C2/mac1c2_7

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1c2_7_4812	50	140	0.1	900	0.08	100	185	13.99

Subdirectory: mac1_C2/mac1c2_8

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1c2_8_4813	50	140	0.1	900	0.08	100	185	13.99

Subdirectory: mac1_C2/mac1c2_9

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1c2_9_4814	50	140	0.1	900	0.08	100	185	13.99

Subdirectory: mac1_C2/mac1c2_10

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1c2_10_4815	50	140	0.1	900	0.08	100	185	13.99

Subdirectory: mac1_C2/mac1c2_11

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
mac1c2_11_4816	25	165	0.1	1400	0.08	100	185	13.99
mac1c2_11_bg_4817	25	165	1	140	0.8	100	185	13.99

mac1c2_11 is the same as the first crystal (mac1c2_3) but vector along the unused portion, over a wider angle range.

Saved a focal stack: dscan oacz -.02 .02 10 .1, image prefix: mac1c2_11_oac_zoom2.

xia2 processing

	mac1c2_3_4809	mac1c2_5_4810	mac1c2_7_4812	mac1c2_8_4813	mac1c2_10_4815	mac1c2_11_4816
Mosaic spread	0.049	0.062	0.261	0.335	0.108	0.338
Resolution	1.73	2.22	1.9	2.22	1.9	1.77
Unit Cell	[134.97, 30.49, 37.87, 90.0, 98.76, 90.0]	[135.25, 30.53, 37.94, 90.0, 98.71, 90.0]	[135.63, 30.65, 38.05, 90.0, 98.76, 90.0]	[134.86, 30.45, 37.8, 90.0, 98.8, 90.0]	[132.8, 30.01, 37.27, 90.0, 98.9, 90.0]	[134.93, 30.49, 37.86, 90.0, 98.79, 90.0]
Image range	[1, 900]	[1, 900]	[1, 900]	[1, 900]	[1, 900]	[1, 1400]
Completeness	71.6	68.5	73.0	63.2	63.0	92.9
Multiplicity	2.4	2.4	2.3	2.6	2.4	2.8
I/sigma	3.8	10.1	9.1	7.5	7.2	8.6
Rpim	0.107	0.147	0.078	0.172	0.101	0.084
Wilson B factor	17.7	19.48	23.57	24.17	25.72	19.53
Space group	C 1 2 1	C 1 2 1	C 1 2 1	C 1 2 1	C 1 2 1	C 1 2 1

setup change

Installed cryostream end-on, and set temperature to 277 K. To avoid damaging folate, we turned off all lights in the hutch, and added a light source for centering with an amber filter.

9. DHFR-Folate

Steve mounted a DHFR-Folate crystal from well D2 of DHFR tray #2 (DHFR samples were looped in the Ando lab cold room on the previous day: this was labeled "sample #1", see Steve's Ando Lab notebook #3, p. 70).

Subdirectory: dhfr_fol/dhfr_fol_1

Took snapshots with the on-axis camera every 30˚, prefix: dhfr_fol_1_oac_zoom4

Changed beam size to 100 x 100 µm.

Vector scan.

prefix	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
dhfr_fol_1_4818	360	0.1	3600	0.01	100	185	13.99
dhfr_fol_1_bg_4819	360	1	360	0.1	100	185	13.99
dhfr_fol_1_4820	360	0.1	3600	0.01	100	185	13.99
dhfr_fol_1_4821	360	0.1	3600	0.01	100	185	13.99
dhfr_fol_1_4822	360	0.1	3600	0.01	100	185	13.99

Scans 4820 - 4822 were repeated on the right hand side of the crystal to estimate the dose tolerance.

xia2 processing

Poor diffraction from the beginning of the dataset. Reprocessed with frames 1800-3600 only

	dhfr_fol_1_4818	dhfr_fol_1_4820	dhfr_fol_1_4821	dhfr_fol_1_4822
Mosaic spread	0.092	0.098	0.103	0.109
Resolution	1.69	1.64	1.68	1.74
Unit Cell	[34.6, 44.65, 101.07, 90.0, 90.0, 90.0]	[34.52, 44.65, 101.08, 90.0, 90.0, 90.0]	[34.49, 44.63, 101.06, 90.0, 90.0, 90.0]	[34.48, 44.63, 101.04, 90.0, 90.0, 90.0]
Image range	[1800, 3600]	[1, 3600]	[1, 3600]	[1, 3600]
Completeness	99.3	99.4	99.4	99.6
Multiplicity	6.6	13.3	13.3	13.3
I/sigma	8.0	7.7	8.1	8.2
Rpim	0.064	0.045	0.045	0.047
Wilson B factor	23.11	22.67	23.96	25.6
Space group	P 21 21 21	P 21 21 21	P 21 21 21	P 21 21 21

molecular replacement (dimple)

Processed with dimple, using 1rx7 as a model. Density looks great.

Clear density for folate.
We have good density for a region of the Met20 loop (residues 15-21) that differs from the pdb deposition, despite using identical crystallization conditions. Interesting!

10. DHFR-Folate

Steve mounted another DHFR-Folate crystal from the same well / tray (labeled "sample #2" in Steve's Ando Lab notebook #3, p. 70).

Subdirectory: dhfr_fol/dhfr_fol_2

Took snapshots with the on-axis camera every 30˚, prefix: dhfr_fol_2_oac_zoom4.

Changed beam size to 30 x 30 µm.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
dhfr_fol_2_4823	0	360	0.1	3600	0.02	100	185	13.99

This crystal has very weak diffraction (too small?)

11. DHFR-Folate

Mounted another DHFR-Folate crystal from the same well / tray (labeled "sample #3" in Steve's Ando Lab notebook #3, p. 70). This one is thin and long.

Subdirectory: dhfr_fol/dhfr_fol_3

Took snapshots with the on-axis camera every 30˚, prefix: dhfr_fol_3_oac_zoom4.

Vector scan along the length of the crystal.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
dhfr_fol_3_4824	0	360	0.1	3600	0.05	100	185	13.99
dhfr_fol_3_bg_4825	0	360	1	360	0.5	100	185	13.99

xia2 processing

	dhfr_fol_3_4824
Mosaic spread	0.418
Resolution	2.16
Unit Cell	[34.45, 43.73, 98.59, 90.0, 90.0, 90.0]
Image range	[1, 3600]
Completeness	100.0
Multiplicity	12.6
I/sigma	6.1
Rpim	0.347
Wilson B factor	35.79
Space group	P 21 21 21

12. DHFR-Folate

Mounted another DHFR-Folate crystal from the same well / tray (labeled "sample #4" in Steve's Ando Lab notebook #3, p. 70). This is a small crystal, on the end of the loop (short and squat).

Subdirectory: dhfr_fol/dhfr_fol_4

Took snapshots with the on-axis camera every 30˚, prefix: dhfr_fol_4_oac_zoom4.

Changed beam size to 100 x 100 µm.

prefix	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
dhfr_fol_4_4826	360	0.1	3600	0.02	100	185	13.99
dhfr_fol_4_bg_4827	360	1	360	0.2	100	185	13.99
dhfr_fol_4_bg_4828	360	1	360	0.2	100	185	13.99

The first background was taken through an empty part of the loop, the second was taken through the capillary only (the usual method). I'm curious if accounting for the Kapton scatter will be helpful or not.

By the end of data collection, I noticed quite a bit of condensation on the capillary -- probably the cooling was not working well.

xia2 processing

	dhfr_fol_4_4826
Mosaic spread	0.199
Resolution	1.84
Unit Cell	[34.57, 44.71, 101.06, 90.0, 90.0, 90.0]
Image range	[1, 3600]
Completeness	100.0
Multiplicity	13.2
I/sigma	6.5
Rpim	0.065
Wilson B factor	25.17
Space group	P 21 21 21

13. DHFR-Folate-NADP

dhfr_fol_ndap_1_oac_zoom4

Steve mounted a DHFR-Folate-NADP sample from DHFR tray #1, well C4 (sample #5 from Steve's notebook #3, p. 70). The crystal is small and thin.

Subdirectory: dhfr_fol_nadp/dhfr_fol_nadp_1

Snapped one image using the on-axis camera, prefix: dhfr_fol_nadp_1_oac_zoom4.

Since it's so tiny, I'll just take a small wedge of data using a beam matching the crystal shape.

Changed beam size to 20 µm (height) x 100 µm (width).

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
dhfr_fol_nadp_1_4829	215	220	0.1	50	1	100	185	13.99
dhfr_fol_nadp_1_4830	0	180	0.1	1800	0.04	100	185	13.99

Wow, it diffracts pretty well, I'm shocked.

xia2 processing

	dhfr_fol_nadp_1_4829	dhfr_fol_nadp_1_4830
Mosaic spread	0.089	0.073
Resolution	1.17	1.95
Unit Cell	[34.43, 45.68, 98.92, 90.0, 90.0, 90.0]	[34.42, 45.66, 98.97, 90.0, 90.0, 90.0]
Image range	[1, 50]	[600, 1800]
Completeness	14.3	98.8
Multiplicity	1.2	4.4
I/sigma	2.5	2.6
Rpim	0.116	0.263
Wilson B factor	6.5	14.32
Space group	P 21 21 21	P 21 21 21

14. DHFR-Folate-NADP

Steve mounted a DHFR-Folate-NADP sample from the same tray / well (sample #6 from Steve's notebook #3, p. 70). Also quite small.

Subdirectory: dhfr_fol_nadp/dhfr_fol_nadp_2

Snapped images every 30˚, prefix: dhfr_fol_nadp_2_oac_zoom4.

Changed beam size to 30 µm (height) x 100 µm (width).

Let's go for a complete dataset.

prefix	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
dhfr_fol_nadp_2_4831	180	0.1	1800	0.04	100	185	13.99
dhfr_fol_nadp_2_bg_4832	180	1	180	0.4	100	185	13.99
dhfr_fol_nadp_2_bg_4833	180	1	180	0.4	100	185	13.99

The first background was taken off the tip of the loop, through the capillary only (conventional method), while the second was taken through an empty part of the loop.

xia2 processing

	dhfr_fol_nadp_2_4831
Mosaic spread	0.059
Resolution	1.6
Unit Cell	[34.44, 45.67, 98.91, 90.0, 90.0, 90.0]
Image range	[600, 1800]
Completeness	99.1
Multiplicity	4.4
I/sigma	2.8
Rpim	0.136
Wilson B factor	11.1
Space group	P 21 21 21

molecular replacement (dimple)

Ran dimple pipeline using pdb model 4p3q. It looks like a pretty good structure, density for folate and NADP is clear. Shocked!

Clear density for folate and NADP.

Done!

2026-03-25 @ CHESS 7b2

Goals

Participants

Data

Beamline setup

Samples

Data collection

1. Mac1 (P43)

2. Lysozyme

3. Mac1 (P43)

4. Mac1 (P43)

5. Mac1 (C2)

6. Mac1 (C2)

7. Mac1 (C2)

8. Mac1 (C2)

9. DHFR-Folate

10. DHFR-Folate

11. DHFR-Folate

12. DHFR-Folate

13. DHFR-Folate-NADP

14. DHFR-Folate-NADP

Comments

1. Mac1 (P4₃)

3. Mac1 (P4₃)

4. Mac1 (P4₃)