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PDBsum entry 4bbk

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Cell adhesion PDB id
4bbk

 

 

 

 

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Contents
Protein chain
121 a.a.
Ligands
GOL
Waters ×49
PDB id:
4bbk
Name: Cell adhesion
Title: Structural and functional characterisation of the kindlin-1 pleckstrin homology domain
Structure: Fermitin family homolog 1. Chain: a. Fragment: pleckstrin homology domain, residues 178-323. Synonym: kindlin-1. Engineered: yes
Source: Mus musculus. House mouse. Organism_taxid: 10090. Expressed in: escherichia coli. Expression_system_taxid: 469008. Expression_system_variant: rosetta (plyss/rare).
Resolution:
2.10Å     R-factor:   0.184     R-free:   0.213
Authors: L.A.Yates,C.N.Lumb,N.N.Brahme,R.Zalyte,L.E.Bird,L.De Colibus, R.J.Owens,D.A.Calderwood,M.S.P.Sansom,R.J.C.Gilbert
Key ref: L.A.Yates et al. (2012). Structural and functional characterization of the kindlin-1 pleckstrin homology domain. J Biol Chem, 287, 43246-43261. PubMed id: 23132860
Date:
25-Sep-12     Release date:   14-Nov-12    
PROCHECK
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 Headers
 References

Protein chain
Pfam   ArchSchema ?
P59113  (FERM1_MOUSE) -  Fermitin family homolog 1 from Mus musculus
Seq:
Struc:
 
Seq:
Struc:
677 a.a.
121 a.a.
Key:    PfamA domain  Secondary structure  CATH domain

 Enzyme reactions 
   Enzyme class: E.C.?
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]

 

 
J Biol Chem 287:43246-43261 (2012)
PubMed id: 23132860  
 
 
Structural and functional characterization of the kindlin-1 pleckstrin homology domain.
L.A.Yates, C.N.Lumb, N.N.Brahme, R.Zalyte, L.E.Bird, L.De Colibus, R.J.Owens, D.A.Calderwood, M.S.Sansom, R.J.Gilbert.
 
  ABSTRACT  
 
Inside-out activation of integrins is mediated via the binding of talin and kindlin to integrin β-subunit cytoplasmic tails. The kindlin FERM domain is interrupted by a pleckstrin homology (PH) domain within its F2 subdomain. Here, we present data confirming the importance of the kindlin-1 PH domain for integrin activation and its x-ray crystal structure at a resolution of 2.1 Å revealing a C-terminal second α-helix integral to the domain but found only in the kindlin protein family. An isoform-specific salt bridge occludes the canonical phosphoinositide binding site, but molecular dynamics simulations display transient switching to an alternative open conformer. Molecular docking reveals that the opening of the pocket would enable potential ligands to bind within it. Although lipid overlay assays suggested the PH domain binds inositol monophosphates, surface plasmon resonance demonstrated weak affinities for inositol 3,4,5-triphosphate (Ins(3,4,5)P(3); K(D) ∼100 μm) and no monophosphate binding. Removing the salt bridge by site-directed mutagenesis increases the PH domain affinity for Ins(3,4,5)P(3) as measured by surface plasmon resonance and enables it to bind PtdIns(3,5)P(2) on a dot-blot. Structural comparison with other PH domains suggests that the phosphate binding pocket in the kindlin-1 PH domain is more occluded than in kindlins-2 and -3 due to its salt bridge. In addition, the apparent affinity for Ins(3,4,5)P(3) is affected by the presence of PO(4) ions in the buffer. We suggest the physiological ligand of the kindlin-1 PH domain is most likely not an inositol phosphate but another phosphorylated species.
 

 

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