9R4A | pdb_00009r4a

Spitrobot-2 advances time-resolvedcryo-trapping crystallography to under 25 ms: Human insulin, pH 4.5 (50 ms soaking)

• PDB DOI: https://doi.org/10.2210/pdb9R4A/pdb

• Classification: HORMONE
• Organism(s): Homo sapiens
• Expression System: Saccharomyces cerevisiae
• Mutation(s): No 


• Deposited: 2025-05-07 Released: 2025-12-03 
• Deposition Author(s): Spiliopoulou, M., Hatton, C.E., Mehrabi, P., Schulz, E.C.
• Funding Organization(s): Max Planck Society, European Research Council (ERC), German Research Foundation (DFG), German Federal Ministry for Education and Research

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.45 Å
• R-Value Free: 
  0.196 (Depositor) 
• R-Value Work: 
  0.170 (Depositor) 
• R-Value Observed: 
  0.172 (Depositor) 

Starting Model: experimental

Literature

Spitrobot-2 advances time-resolved cryo-trapping crystallography to under 25 ms.

Spiliopoulou, M., Hatton, C.E., Kollewe, M., Leimkohl, J.P., Schikora, H., Tellkamp, F., Mehrabi, P., Schulz, E.C.

(2025) Commun Chem 8: 363-363

• PubMed: 41266557 
• DOI: https://doi.org/10.1038/s42004-025-01784-9
• Primary Citation Related Structures: 
  9R45, 9R46, 9R47, 9R48, 9R49, 9R4A, 9R4B, 9R4C, 9R4E, 9R4F, 9R4G, 9R4H


• PubMed Abstract: 
  

  We previously introduced the spitrobot, a protein crystal plunging system that enables reaction quenching via cryo-trapping with a time resolution in the millisecond range. Here we present the next generation, spitrobot-2, as an integrated benchtop device. User-friendliness has been improved by semi-automatic sample exchange. Moreover, a fully automated shutter shields the liquid nitrogen from the humidified environment, improving sample integrity. Most importantly, the cryo-trapping delay time has been reduced to 23 ms, making spitrobot-2 twice as fast as the previous generation. This further expands the number of target systems that can be addressed by cryo-trapping time-resolved crystallography. Using 12 crystal structures of three independent model systems, we demonstrate successful cryo-trapping via observation of conformational changes and ligand binding within 25 ms. These improvements increase the convenient access to cryo-trapping, time-resolved X-ray crystallography empowering the MX community with efficient tools to advance research in structural biology.

---

Organizational Affiliation: 
• University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany.
Institute for Nanostructure and Solid State Physics, Universität Hamburg, Hamburg, Germany.
Max-Planck-Institute for Structure and Dynamics of Matter, Hamburg, Germany.
Max-Planck-Institute for Structure and Dynamics of Matter, Hamburg, Germany. [e-mail].
Institute for Nanostructure and Solid State Physics, Universität Hamburg, Hamburg, Germany. [e-mail].
Max-Planck-Institute for Structure and Dynamics of Matter, Hamburg, Germany. [e-mail].
University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany. [e-mail].
Institute for Nanostructure and Solid State Physics, Universität Hamburg, Hamburg, Germany. [e-mail].
Max-Planck-Institute for Structure and Dynamics of Matter, Hamburg, Germany. [e-mail].

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - A1B1 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content 

• Total Structure Weight: 5.91 kDa 
• Atom Count: 503 
• Modeled Residue Count: 51 
• Deposited Residue Count: 51 
• Unique protein chains: 2

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Insulin A chain	A	21	Homo sapiens	Mutation(s): 0  Gene Names: INS
UniProt & NIH Common Fund Data Resources
Find proteins for P01308 (Homo sapiens) Explore P01308  Go to UniProtKB:  P01308
PHAROS:  P01308 GTEx:  ENSG00000254647

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Insulin B chain	B	30	Homo sapiens	Mutation(s): 0  Gene Names: INS
UniProt & NIH Common Fund Data Resources
Find proteins for P01308 (Homo sapiens) Explore P01308  Go to UniProtKB:  P01308
PHAROS:  P01308 GTEx:  ENSG00000254647

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
SO4 (Subject of Investigation/LOI)	C [auth B]	SULFATE ION O4 S QAOWNCQODCNURD-UHFFFAOYSA-L

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.45 Å
• R-Value Free:  0.196 (Depositor) 
• R-Value Work:  0.170 (Depositor) 
• R-Value Observed: 0.172 (Depositor) 

Space Group: I 2₁ 3

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 78.345	α = 90
b = 78.345	β = 90
c = 78.345	γ = 90

Software Package:

Software Name	Purpose
XDS	data reduction
autoPROC	data reduction
Aimless	data scaling
autoPROC	data scaling
PHASER	phasing
REFMAC	refinement

Structure Validation

Entry History 

& Funding Information

Deposition Data

• Released Date: 2025-12-03 
Deposition Author(s): Spiliopoulou, M., Hatton, C.E., Mehrabi, P., Schulz, E.C.

---

Funding Organization	Location	Grant Number
Max Planck Society	Germany	--
European Research Council (ERC)	European Union	--
German Research Foundation (DFG)	Germany	458246365
German Research Foundation (DFG)	Germany	451079909
German Federal Ministry for Education and Research	Germany	01KI2114

Revision History  

• Version 1.0: 2025-12-03
  Type: Initial release