PDBsum entry 3lvr

Protein transport

PDB id: 3lvr

Contents

Protein chain

419 a.a. *

Ligands

GDP-AF3

Metals

_CA

_ZN

_MG

Waters ×6

* Residue conservation analysis

PDB id:

3lvr

Name:

Protein transport

Title:

The crystal structure of asap3 in complex with arf6 in transition state soaked with calcium

Structure:

Arf-gap with sh3 domain, ank repeat and ph domain- containing protein 3, adp-ribosylation factor 6. Chain: e. Fragment: gap and ankyrin domain, residues 416-697, residues 11-175. Synonym: asap3, development and differentiation-enhancing factor-like 1, protein up-regulated in liver cancer 1, arf6, uplc1. Engineered: yes. Other_details: missing the n-terminus amphipathic helix for arf6

Source:

Homo sapiens, synthetic construct. Human. Organism_taxid: 9606, 32630. Gene: asap3, arf6. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

3.38Å R-factor: 0.211 R-free: 0.281

Authors:

S.A.Ismail,I.R.Vetter,B.Sot,A.Wittinghofer

Key ref:

S.A.Ismail et al. (2010). The structure of an Arf-ArfGAP complex reveals a Ca2+ regulatory mechanism. Cell, 141, 812-821. PubMed id: 20510928

Date:

22-Feb-10 Release date: 09-Jun-10

Protein chain

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

Seq: 175 a.a.

Struc: 419 a.a.*

Protein chain

Q8TDY4  (ASAP3_HUMAN) -  Arf-GAP with SH3 domain, ANK repeat and PH domain-containing protein 3 from Homo sapiens

Seq: 903 a.a.

Struc: 419 a.a.*

* PDB and UniProt seqs differ at 165 residue positions (black crosses)

Enzyme reactions

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

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

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

reference

Cell 141:812-821 (2010)

PubMed id: 20510928

The structure of an Arf-ArfGAP complex reveals a Ca2+ regulatory mechanism.

S.A.Ismail, I.R.Vetter, B.Sot, A.Wittinghofer.

ABSTRACT

Arfs are small G proteins that have a key role in vesicle trafficking and cytoskeletal remodeling. ArfGAP proteins stimulate Arf intrinsic GTP hydrolysis by a mechanism that is still unresolved. Using a fusion construct we solved the structure of the ArfGAP ASAP3 in complex with Arf6 in the transition state. This structure clarifies the ArfGAP catalytic mechanism and shows a glutamine((Arf6)) and an arginine finger((ASAP3)) as the important catalytic residues. Unexpectedly the structure shows a calcium ion, liganded by both proteins in the complex interface, stabilizing the interaction and orienting the catalytic machinery. Calcium stimulates the GAP activity of ASAPs, but not other members of the ArfGAP family. This type of regulation is unique for GAPs and any other calcium-regulated processes and hints at a crosstalk between Ca(2+) and Arf signaling.