7QAC | pdb_00007qac

The T2 structure of polycrystalline cubic human insulin

• PDB DOI: https://doi.org/10.2210/pdb7QAC/pdb

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


• Deposited: 2021-11-16 Released: 2023-06-21 
• Deposition Author(s): Karavassili, F., Triandafillidis, D.P., Valmas, A., Spiliopoulou, M., Fili, S., Kontou, P., Bowler, M.W., Von Dreele, R.B., Fitch, A., Margiolaki, I.
• Funding Organization(s): General Secretariat for Research and Technology (GSRT), Hellenic Foundation for Research and Innovation (HFRI)

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Experimental Data Snapshot

• Method: POWDER DIFFRACTION
• Resolution: 2.29 Å

Starting Model: experimental

Literature

The T 2 structure of polycrystalline cubic human insulin.

Triandafillidis, D.P., Karavassili, F., Spiliopoulou, M., Valmas, A., Athanasiadou, M., Nikolaras, G., Fili, S., Kontou, P., Bowler, M.W., Chasapis, C.T., Von Dreele, R.B., Fitch, A.N., Margiolaki, I.

(2023) Acta Crystallogr D Struct Biol 79: 374-386

• PubMed: 37039669 
• DOI: https://doi.org/10.1107/S2059798323001328
• Primary Citation Related Structures: 
  7QAC


• PubMed Abstract: 
  

  The polymorphism of human insulin upon pH variation was characterized via X-ray powder diffraction, employing a crystallization protocol previously established for co-crystallization with phenolic derivatives. Two distinct rhombohedral (R3) polymorphs and one cubic (I2 ₁ 3) polymorph were identified with increasing pH, corresponding to the T ₆ , T ₃ R ₃ ^f and T ₂ conformations of insulin, respectively. The structure of the cubic T ₂ polymorph was determined via multi-profile stereochemically restrained Rietveld refinement at 2.7 Å resolution. This constitutes the first cubic insulin structure to be determined from crystals grown in the presence of zinc ions, although no zinc binding was observed. The differences of the polycrystalline variant from other cubic insulin structures, as well as the nature of the pH-driven phase transitions, are discussed in detail.

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Organizational Affiliation: 
• Section of Genetics, Cell Biology and Development, Department of Biology, University of Patras, 26504 Patras, Greece.
European Molecular Biology Laboratory, 71 Avenue des Martyrs, 38042 Grenoble, France.
Institute of Chemical Biology, National Hellenic Research Foundation, 11635 Athens, Greece.
Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439, USA.
European Synchrotron Radiation Facility, BP 220, 38043 Grenoble CEDEX 9, France.

Biological Assembly 1  

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

Biological assembly 1 assigned by authors.

Macromolecule Content 

• Total Structure Weight: 5.82 kDa 
• Atom Count: 467 
• 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

Experimental Data & Validation

Experimental Data

• Method: POWDER DIFFRACTION
• Resolution: 2.29 Å

Space Group: I 2₁ 3

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 78.86015	α = 90
b = 78.86015	β = 90
c = 78.86015	γ = 90

Software Package:

Software Name	Purpose
GSAS	refinement
PRODD	data reduction
MOLREP	phasing
Coot	model building

Structure Validation

Entry History 

& Funding Information

Deposition Data

• Released Date: 2023-06-21 
Deposition Author(s): Karavassili, F., Triandafillidis, D.P., Valmas, A., Spiliopoulou, M., Fili, S., Kontou, P., Bowler, M.W., Von Dreele, R.B., Fitch, A., Margiolaki, I.

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Funding Organization	Location	Grant Number
General Secretariat for Research and Technology (GSRT)	European Union	--
Hellenic Foundation for Research and Innovation (HFRI)	Greece	3051

Revision History  

• Version 1.0: 2023-06-21
  Type: Initial release
  
• Version 1.1: 2023-07-19
  Changes: Data collection
• Version 1.2: 2023-08-16
  Changes: Data collection
• Version 1.3: 2024-02-07
  Changes: Refinement description
• Version 1.4: 2024-10-09
  Changes: Structure summary