1kfx
From Proteopedia
(New page: 200px<br /> <applet load="1kfx" size="450" color="white" frame="true" align="right" spinBox="true" caption="1kfx, resolution 3.15Å" /> '''Crystal Structure o...) |
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caption="1kfx, resolution 3.15Å" /> | caption="1kfx, resolution 3.15Å" /> | ||
'''Crystal Structure of Human m-Calpain Form I'''<br /> | '''Crystal Structure of Human m-Calpain Form I'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1KFX is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Active as [http://en.wikipedia.org/wiki/Hydrolase Hydrolase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.22.52 and 3.4.22.53 3.4.22.52 and 3.4.22.53] Full crystallographic information is available from [http:// | + | 1KFX is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Active as [http://en.wikipedia.org/wiki/Hydrolase Hydrolase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.22.52 and 3.4.22.53 3.4.22.52 and 3.4.22.53] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KFX OCA]. |
==Reference== | ==Reference== | ||
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[[Category: thiol-protease]] | [[Category: thiol-protease]] | ||
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Revision as of 14:13, 15 February 2008
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Crystal Structure of Human m-Calpain Form I
Overview
Calpains (calcium-dependent cytoplasmic cysteine proteinases) are, implicated in processes such as cytoskeleton remodeling and signal, transduction. The 2.3-A crystal structure of full-length heterodimeric, [80-kDa (dI-dIV) + 30-kDa (dV+dVI)] human m-calpain crystallized in the, absence of calcium reveals an oval disc-like shape, with the papain-like, catalytic domain dII and the two calmodulin-like domains dIV+dVI occupying, opposite poles, and the tumor necrosis factor alpha-like beta-sandwich, domain dIII and the N-terminal segments dI+dV located between. Compared, with papain, the two subdomains dIIa+dIIb of the catalytic unit are, rotated against one another by 50 degrees, disrupting the active site and, the substrate binding site, explaining the inactivity of calpains in the, absence of calcium. Calcium binding to an extremely negatively charged, loop of domain dIII (an electrostatic switch) could release the adjacent, barrel-like subdomain dIIb to move toward the helical subdomain dIIa, allowing formation of a functional catalytic center. This switch loop, could also mediate membrane binding, thereby explaining calpains' strongly, reduced calcium requirements in vivo. The activity status at the catalytic, center might be further modulated by calcium binding to the calmodulin, domains via the N-terminal linkers.
About this Structure
1KFX is a Protein complex structure of sequences from Homo sapiens. Active as Hydrolase, with EC number and 3.4.22.53 3.4.22.52 and 3.4.22.53 Full crystallographic information is available from OCA.
Reference
The crystal structure of calcium-free human m-calpain suggests an electrostatic switch mechanism for activation by calcium., Strobl S, Fernandez-Catalan C, Braun M, Huber R, Masumoto H, Nakagawa K, Irie A, Sorimachi H, Bourenkow G, Bartunik H, Suzuki K, Bode W, Proc Natl Acad Sci U S A. 2000 Jan 18;97(2):588-92. PMID:10639123
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