1ito: Difference between revisions

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

In order to elucidate the substrate specificity of the Sn subsites (n=1-3) of cathepsin B, its crystal structure inhibited by E64c [(+)-(2S,3S)-3-(1-[N-(3-methylbutyl)amino]-leucylcarbonyl)oxirane-2-carbox ylic acid] was analyzed by the X-ray diffraction method. Iterative manual rebuilding and convenient conjugate refinement of structure decreased R- and free R-factors to 19.7% and to 23.9%, respectively, where 130 water molecules were included for the refinement using 14,759 independent reflections from 10 to 2.3 A resolution. The epoxy carbonyl carbon of E64c was covalently bonded to the Cys(29) S(gamma) atom and the remaining parts were located at Sn subsites (n=1-3). The substrate specificity of these subsites was characterized based on their interactions with the inhibitor. Base on these structural data, we developed a novel cathepsin B-specific noncovalent-type inhibitor, which may bind to S2'-S3. The molecular design of possessing structural elements of both CA074 and E64c, assisted by energy minimization and molecular dynamics (MD) simulation, may lead to a new lead noncovalent-type inhibitor.

1ITO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] with <scene name='pdbligand=E6C:'>E6C</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cathepsin_B Cathepsin B], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.22.1 3.4.22.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ITO OCA].  

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