1is7: Difference between revisions

[[Image:1is7.gif|left|200px]]<br /><applet load="1is7" size="350" color="white" frame="true" align="right" spinBox="true"  

In the presence of phenylalanine, GTP cyclohydrolase I feedback regulatory protein (GFRP) forms a stimulatory 360-kDa complex with GTP cyclohydrolase I (GTPCHI), which is the rate-limiting enzyme in the biosynthesis of tetrahydrobiopterin. The crystal structure of the stimulatory complex reveals that the GTPCHI decamer is sandwiched by two GFRP homopentamers. Each GFRP pentamer forms a symmetrical five-membered ring similar to beta-propeller. Five phenylalanine molecules are buried inside each interface between GFRP and GTPCHI, thus enhancing the binding of these proteins. The complex structure suggests that phenylalanine-induced GTPCHI x GFRP complex formation enhances GTPCHI activity by locking the enzyme in the active state.

1IS7 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with <scene name='pdbligand=K:'>K</scene> and <scene name='pdbligand=PHE:'>PHE</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/GTP_cyclohydrolase_I GTP cyclohydrolase I], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.4.16 3.5.4.16] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1IS7 OCA].  

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