1xfd

From Proteopedia

proteopedia linkproteopedia link

spinqualitylabelsall models PDB ID 1xfd Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image
, resolution 3.00Å
Ligands:	, , ,
Gene:	DPPX (Homo sapiens)
Resources:	FirstGlance, OCA, PDBsum, RCSB
Coordinates:	save as pdb, mmCIF, xml

Structure of a human A-type Potassium Channel Accelerating factor DPPX, a member of the dipeptidyl aminopeptidase family

Overview

It has recently been reported that dipeptidyl aminopeptidase X (DPPX) interacts with the voltage-gated potassium channel Kv4 and that co-expression of DPPX together with Kv4 pore forming alpha-subunits, and potassium channel interacting proteins (KChIPs), reconstitutes properties of native A-type potassium channels in vitro. Here we report the X-ray crystal structure of the extracellular domain of human DPPX determined at 3.0A resolution. This structure reveals the potential for a surface electrostatic change based on the protonation state of histidine. Subtle changes in extracellular pH might modulate the interaction of DPPX with Kv4.2 and possibly with other proteins. We propose models of DPPX interaction with the voltage-gated potassium channel complex. The dimeric structure of DPPX is highly homologous to the related protein DPP-IV. Comparison of the active sites of DPPX and DPP-IV reveals loss of the catalytic serine residue but the presence of an additional serine near the "active" site. However, the arrangement of residues is inconsistent with that of canonical serine proteases and DPPX is unlikely to function as a protease (dipeptidyl aminopeptidase).

About this Structure

1XFD is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.

Reference

Structure of a human A-type potassium channel interacting protein DPPX, a member of the dipeptidyl aminopeptidase family., Strop P, Bankovich AJ, Hansen KC, Garcia KC, Brunger AT, J Mol Biol. 2004 Oct 29;343(4):1055-65. PMID:15476821

Page seeded by OCA on Mon Mar 31 00:48:51 2008