'''Crystal structure of the human carboxypeptidase N (Kininase I) catalytic domain'''
===Crystal structure of the human carboxypeptidase N (Kininase I) catalytic domain===
==Overview==
<!--
Human carboxypeptidase N (CPN), a member of the CPN/E subfamily of "regulatory" metallo-carboxypeptidases, is an extracellular glycoprotein synthesized in the liver and secreted into the blood, where it controls the activity of vasoactive peptide hormones, growth factors and cytokines by specifically removing C-terminal basic residues. Normally, CPN circulates in blood plasma as a hetero-tetramer consisting of two 83 kDa (CPN2) domains each flanked by a 48 to 55 kDa catalytic (CPN1) domain. We have prepared and crystallized the recombinant C-terminally truncated catalytic domain of human CPN1, and have determined and refined its 2.1 A crystal structure. The structural analysis reveals that CPN1 has a pear-like shape, consisting of a 319 residue N-terminal catalytic domain and an abutting, cylindrically shaped 79 residue C-terminal beta-sandwich transthyretin (TT) domain, more resembling CPD-2 than CPM. Like these other CPN/E members, two surface loops surrounding the active-site groove restrict access to the catalytic center, offering an explanation for why some larger protein carboxypeptidase inhibitors do not inhibit CPN. Modeling of the Pro-Phe-Arg C-terminal end of the natural substrate bradykinin into the active site shows that the S1' pocket of CPN1 might better accommodate P1'-Lys than Arg residues, in agreement with CPN's preference for cleaving off C-terminal Lys residues. Three Thr residues at the distal TT edge of CPN1 are O-linked to N-acetyl glucosamine sugars; equivalent sites in the membrane-anchored CPM are occupied by basic residues probably involved in membrane interaction. In tetrameric CPN, each CPN1 subunit might interact with the central leucine-rich repeat tandem of the cognate CPN2 subunit via a unique hydrophobic surface patch wrapping around the catalytic domain-TT interface, exposing the two active centers.
The line below this paragraph, {{ABSTRACT_PUBMED_17157876}}, adds the Publication Abstract to the page
(as it appears on PubMed at http://www.pubmed.gov), where 17157876 is the PubMed ID number.
-->
{{ABSTRACT_PUBMED_17157876}}
==About this Structure==
==About this Structure==
Line 38:
Line 42:
[[Category: Transthyretin-like domain]]
[[Category: Transthyretin-like domain]]
[[Category: Zinc peptidase]]
[[Category: Zinc peptidase]]
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 09:51:42 2008''
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 04:10:46 2008''
Revision as of 01:10, 29 July 2008
This article has been automatically seeded. Changes to this page should pertain to the PDB entry only and not to the protein or biomolecule in general.
2NSM is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Crystal structure of the human carboxypeptidase N (kininase I) catalytic domain., Keil C, Maskos K, Than M, Hoopes JT, Huber R, Tan F, Deddish PA, Erdos EG, Skidgel RA, Bode W, J Mol Biol. 2007 Feb 16;366(2):504-16. Epub 2006 Nov 11. PMID:17157876
