Title : Structure of a human A-type
potassium channel interacting protein
DPPX , a member of the dipeptidyl
aminopeptidase family
Abstract :
- It has recently been reported that dipeptidyl aminopeptidase X ( DPPX ) interacts with the voltage-gated potassium channel 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 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 )
Output (sent_index, trigger,
protein,
sugar,
site):
Output(Part-Of) (sent_index,
protein,
site):
- 2. DPPX, domain
- 7. DPP-IV, sites
- 7. DPPX, sites
*Output_Site_Fusion* (sent_index,
protein,
sugar,
site):