1xfd
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(New page: 200px<br /><applet load="1xfd" size="450" color="white" frame="true" align="right" spinBox="true" caption="1xfd, resolution 3.00Å" /> '''Structure of a human...)
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Revision as of 03:55, 21 November 2007
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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
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