View source for 2m99


==Solution structure of a chymotrypsin inhibitor from the Taiwan cobra==
<StructureSection load='2m99' size='340' side='right'caption='[[2m99]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2m99]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Naja_atra Naja atra]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2M99 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2M99 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR, 20 models</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2m99 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2m99 OCA], [https://pdbe.org/2m99 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2m99 RCSB], [https://www.ebi.ac.uk/pdbsum/2m99 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2m99 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/VKT_NAJAT VKT_NAJAT] Serine protease inhibitor that inhibits chymotrypsin (Ki=25 nM) (PubMed:14990218, PubMed:15698956). Also interacts with vasopressin V2 receptor (V2R/AVPR2) (PubMed:35122240). Inhibits vasopressin binding human V2R in the nanomolar range (Ki=112 nM), and also moderately inhibits vasopressin-induced cAMP production (IC(50)=138 nM). In vivo, intraperitoneal injection of this protein into rats increases diuresis by 2.2-fold, without any loss of electrolytes (PubMed:35122240).<ref>PMID:14990218</ref> <ref>PMID:15698956</ref> <ref>PMID:35122240</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The Taiwan cobra (Naja naja atra) chymotrypsin inhibitor (NACI) consists of 57 amino acids and is related to other Kunitz-type inhibitors such as bovine pancreatic trypsin inhibitor (BPTI) and Bungarus fasciatus fraction IX (BF9), another chymotrypsin inhibitor. Here we present the solution structure of NACI. We determined the NMR structure of NACI with a root-mean-square deviation of 0.37 A for the backbone atoms and 0.73 A for the heavy atoms on the basis of 1,075 upper distance limits derived from NOE peaks measured in its NOESY spectra. To investigate the structural characteristics of NACI, we compared the three-dimensional structure of NACI with BPTI and BF9. The structure of the NACI protein comprises one 310-helix, one alpha-helix and one double-stranded antiparallel beta-sheet, which is comparable with the secondary structures in BPTI and BF9. The RMSD value between the mean structures is 1.09 A between NACI and BPTI and 1.27 A between NACI and BF9. In addition to similar secondary and tertiary structure, NACI might possess similar types of protein conformational fluctuations as reported in BPTI, such as Cys14-Cys38 disulfide bond isomerization, based on line broadening of resonances from residues which are mainly confined to a region around the Cys14-Cys38 disulfide bond.

NMR solution structure of a Chymotrypsin inhibitor from the Taiwan cobra Naja naja atra.,Lin YJ, Ikeya T, Guntert P, Chang LS Molecules. 2013 Jul 26;18(8):8906-18. doi: 10.3390/molecules18088906. PMID:23896616<ref>PMID:23896616</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 2m99" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Naja atra]]
[[Category: Chang L-S]]
[[Category: Guntert P]]
[[Category: Ikeya T]]
[[Category: Lin Y-J]]