PDBsum entry 6bbp

Lipid binding protein

PDB id: 6bbp

Contents

Protein chain

520 a.a.

Ligands

GTP

4IP

Metals

_MG

PDB id:

6bbp

Name:

Lipid binding protein

Title:

Model for compact volume of truncated monomeric cytohesin-3 (grp1; amino acids 63-399) e161a 6gs arf6 q67l fusion protein

Structure:

Cytohesin-3,adp-ribosylation factor 6. Chain: a. Synonym: arf nucleotide-binding site opener 3,protein arno3,general receptor of phosphoinositides 1,grp1,ph,sec7 and coiled-coil domain- containing protein 3,clm3,sec7 homolog c,msec7-3. Engineered: yes. Mutation: yes

Source:

Mus musculus, homo sapiens. Mouse, human. Organism_taxid: 10090, 9606. Gene: cyth3, grp1, pscd3, arf6. Expressed in: escherichia coli. Expression_system_taxid: 562

Authors:

S.Das,A.W.Malaby,D.G.Lambright

Key ref:

A.W.Malaby et al. (2018). Structural Dynamics Control Allosteric Activation of Cytohesin Family Arf GTPase Exchange Factors. Structure, 26, 106. PubMed id: 29276036

Date:

19-Oct-17 Release date: 10-Jan-18

Protein chain

O08967  (CYH3_MOUSE) -  Cytohesin-3 from Mus musculus

Seq: 399 a.a.

Struc: 520 a.a.*

Protein chain

P62330  (ARF6_HUMAN) -  ADP-ribosylation factor 6 from Homo sapiens

Seq: 175 a.a.

Struc: 520 a.a.*

* PDB and UniProt seqs differ at 13 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.6.5.2 - small monomeric GTPase.
• Reaction: GTP + H2O = GDP + phosphate + H⁺

GTP (Bound ligand (Het Group name = GTP) corresponds exactly) + H2O = GDP + phosphate + H(+)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

Structure 26:106 (2018)

PubMed id: 29276036

Structural Dynamics Control Allosteric Activation of Cytohesin Family Arf GTPase Exchange Factors.

A.W.Malaby, S.Das, S.Chakravarthy, T.C.Irving, O.Bilsel, D.G.Lambright.

ABSTRACT

Membrane dynamic processes including vesicle biogenesis depend on Arf guanosine triphosphatase (GTPase) activation by guanine nucleotide exchange factors (GEFs) containing a catalytic Sec7 domain and a membrane-targeting module such as a pleckstrin homology (PH) domain. The catalytic output of cytohesin family Arf GEFs is controlled by autoinhibitory interactions that impede accessibility of the exchange site in the Sec7 domain. These restraints can be relieved through activator Arf-GTP binding to an allosteric site comprising the PH domain and proximal autoinhibitory elements (Sec7-PH linker and C-terminal helix). Small-angle X-ray scattering and negative-stain electron microscopy were used to investigate the structural organization and conformational dynamics of cytohesin-3 (Grp1) in autoinhibited and active states. The results support a model in which hinge dynamics in the autoinhibited state expose the activator site for Arf-GTP binding, while subsequent C-terminal helix unlatching and repositioning unleash conformational entropy in the Sec7-PH linker to drive exposure of the exchange site.