9ID0

XFEL structure of hNQO1 mixed with NADH in a folded orientation at 300 ms

Summary for 9ID0

• Entry DOI: 10.2210/pdb9id0/pdb
• Descriptor: NAD(P)H dehydrogenase [quinone] 1, NICOTINAMIDE-ADENINE-DINUCLEOTIDE, FLAVIN-ADENINE DINUCLEOTIDE, ... (5 entities in total)
• Functional Keywords: cooperativity, flavoenzyme, quinones, cancer, oxidorreductase, oxidoreductase
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 4
• Total formula weight: 130243.53

Authors

Martin-Garcia, J.M.,Quereda-Moraleda, I.,Grieco, A.,Botha, S. (deposition date: 2025-02-15, release date: 2026-02-11)

Primary citation

Doppler, D.,Grieco, A.,Koh, D.,Manna, A.,Ansari, A.,Alvarez, R.,Karpos, K.,Le, H.,Sonker, M.,Ketawala, G.K.,Mahmud, S.,Quereda-Moraleda, I.,Sen, S.,Pey, A.L.,Letrun, R.,Dorner, K.,Koliyadu, J.C.P.,de Wijn, R.,Bielecki, J.,Han, H.,Kim, C.,Koua, F.H.M.,Round, A.,Sarma, A.,Sato, T.,Schmidt, C.,Vakili, M.,Zabelskii, D.,Bean, R.,Mancuso, A.P.,Schulz, J.,Fromme, R.,Medina, M.,Grant, T.D.,Fromme, P.,Kirian, R.A.,Botha, S.,Manuel Martin-Garcia, J.,Ros, A.
Minimized sample consumption for time-resolved serial crystallography applied to the redox cycle of human NQO1.
Commun Chem, 2026

PubMed Abstract: Sample consumption for serial femtosecond crystallography with X-ray free electron lasers remains a major limitation preventing broader use in macromolecular crystallography. This drawback is exacerbated in time-resolved (TR) experiments, where the amount of sample required per reaction time point is multiplied by the number of time points investigated. To reduce this limitation, we demonstrate a segmented droplet generation strategy coupled to a mix-and-inject approach for TR studies at the European XFEL. The injector produces synchronized droplet trains that enable stable and reproducible injection of protein crystal slurries at significantly reduced flow rates. Using the human flavoenzyme NAD(P)H:quinone oxidoreductase 1 (NQO1) as a test system, we collected diffraction data after mixing with NADH at 0.3 s and 1.2 s delays. The segmented injection approach achieved up to 97% reduction in sample consumption compared with continuous-flow injection while maintaining data quality suitable for TR crystallography. Reproducible electron density features consistent with low-occupancy NADH binding illustrate both the feasibility and the current limits of studying dynamic redox enzymes using this approach. This work establishes segmented droplet generation as a sample-efficient and XFEL-compatible method for future time-resolved serial crystallography experiments.

PubMed: 41611948
DOI: 10.1038/s42004-026-01908-9

Experimental method

X-RAY DIFFRACTION (2.51 Å)