9INS

MONOVALENT CATION BINDING IN CUBIC INSULIN CRYSTALS


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.7 Å

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Monovalent cation binding to cubic insulin crystals

Gursky, O.Li, Y.Badger, J.Caspar, D.L.D.

(1992) Biophys.J. 61: 604-611

  • DOI: 10.1016/S0006-3495(92)81865-9

  • PubMed Abstract: 
  • Two localized monovalent cation binding sites have been identified in cubic insulin from 2.8 A-resolution difference electron density maps comparing crystals in which the Na+ ions have been replaced by Tl+. One cation is buried in a closed cavity bet ...

    Two localized monovalent cation binding sites have been identified in cubic insulin from 2.8 A-resolution difference electron density maps comparing crystals in which the Na+ ions have been replaced by Tl+. One cation is buried in a closed cavity between insulin dimers and is stabilized by interaction with protein carbonyl dipoles in two juxtaposed alternate positions related by the crystal dyad. The second cation binding site, which also involves ligation with carbonyl dipoles, is competitively occupied by one position of two alternate His B10 side chain conformations. The cation occupancy in both sites depends on the net charge on the protein which was varied by equilibrating crystals in the pH range 7-10. Detailed structures of the cation binding sites were inferred from the refined 2-A resolution map of the sodium-insulin crystal at pH 9. At pH 9, the localized monovalent cations account for less than one of the three to four positive counterion charges necessary to neutralize the negative charge on each protein molecule. The majority of the monovalent counterions are too mobile to show up in the electron density maps calculated using data only at resolution higher than 10 A. Monovalent cations of ionic radius less than 1.5 A are required for crystal stability. Replacing Na+ with Cs+, Mg++, Ca++ or La+++ disrupts the lattice order, but crystals at pH 9 with 0.1 M Li+, K+, NH4+, Rb+ or Tl+ diffract to at least 2.8 A resolution.


    Related Citations: 
    • Water Structure in Cubic Insulin Crystals
      Badger, J.,Caspar, D.L.D.
      (1991) Proc.Natl.Acad.Sci.USA 88: 622
    • Structure of the Pig Insulin Dimer in the Cubic Crystal
      Badger, J.,Harris, M.R.,Reynolds, C.D.,Evans, A.C.,Dodson, E.J.,Dodson, G.G.,North, A.C.T.
      (1991) Acta Crystallogr.,Sect.B 47: 127
    • Zinc-Free Cubic Pig Insulin: Crystallization and Structure Determination
      Dodson, E.J.,Dodson, G.G.,Lewitova, A.,Sabesan, M.
      (1978) J.Mol.Biol. 125: 387


    Organizational Affiliation

    Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02254-9110.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
INSULIN (CHAIN A)
A
21Sus scrofaGene Names: INS
Find proteins for P01315 (Sus scrofa)
Go to Gene View: INS
Go to UniProtKB:  P01315
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
INSULIN (CHAIN B)
B
30Sus scrofaGene Names: INS
Find proteins for P01315 (Sus scrofa)
Go to Gene View: INS
Go to UniProtKB:  P01315
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.7 Å
  • Space Group: I 21 3
Unit Cell:
Length (Å)Angle (°)
a = 78.900α = 90.00
b = 78.900β = 90.00
c = 78.900γ = 90.00
Software Package:
Software NamePurpose
PROLSQrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1991-11-07
    Type: Initial release
  • Version 1.1: 2008-03-25
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-11-29
    Type: Derived calculations, Other