1ea7: Difference between revisions
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==Overview== | ==Overview== | ||
We have previously isolated sphericase (Sph), an extracellular mesophilic, serine protease produced by Bacillus sphaericus. The Sph amino acid, sequence is highly homologous to two cold-adapted subtilisins from, Antarctic bacilli S39 and S41 (76% and 74% identity, respectively). Sph is, calcium-dependent, 310 amino acid residues long and has optimal activity, at pH 10.0. S41 and S39 have not as yet been structurally analysed.In the, present work, we determined the crystal structure of Sph by the, Eu/multiwavelength anomalous diffraction method. The structure was, extended to 0.93A resolution and refined to a crystallographic R-factor of, 9.7%. The final model included all 310 amino acid residues, one disulfide, bond, 679 water molecules and five calcium ions. Although Sph is a, mesophilic ... | We have previously isolated sphericase (Sph), an extracellular mesophilic, serine protease produced by Bacillus sphaericus. The Sph amino acid, sequence is highly homologous to two cold-adapted subtilisins from, Antarctic bacilli S39 and S41 (76% and 74% identity, respectively). Sph is, calcium-dependent, 310 amino acid residues long and has optimal activity, at pH 10.0. S41 and S39 have not as yet been structurally analysed.In the, present work, we determined the crystal structure of Sph by the, Eu/multiwavelength anomalous diffraction method. The structure was, extended to 0.93A resolution and refined to a crystallographic R-factor of, 9.7%. The final model included all 310 amino acid residues, one disulfide, bond, 679 water molecules and five calcium ions. Although Sph is a, mesophilic subtilisin, its amino acid sequence is similar to that of the, psychrophilic subtilisins, which suggests that the crystal structure of, these subtilisins is very similar.The presence of five calcium ions bound, to a subtilisin molecule, as found here for Sph, has not been reported for, the subtilisin superfamily. None of these calcium-binding sites correlates, with the well-known high-affinity calcium-binding site (site I or site A), and only one site has been described previously. This calcium-binding, pattern suggests that a reduction in the flexibility of the surface loops, of Sph by calcium binding may be responsible for its adaptation to, mesophilic organisms. | ||
==About this Structure== | ==About this Structure== | ||
1EA7 is a | 1EA7 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Lysinibacillus_sphaericus Lysinibacillus sphaericus] with CA and S as [http://en.wikipedia.org/wiki/ligands ligands]. Structure known Active Site: 1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1EA7 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: subtilisin like protease]] | [[Category: subtilisin like protease]] | ||
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Revision as of 13:59, 5 November 2007
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SPHERICASE
OverviewOverview
We have previously isolated sphericase (Sph), an extracellular mesophilic, serine protease produced by Bacillus sphaericus. The Sph amino acid, sequence is highly homologous to two cold-adapted subtilisins from, Antarctic bacilli S39 and S41 (76% and 74% identity, respectively). Sph is, calcium-dependent, 310 amino acid residues long and has optimal activity, at pH 10.0. S41 and S39 have not as yet been structurally analysed.In the, present work, we determined the crystal structure of Sph by the, Eu/multiwavelength anomalous diffraction method. The structure was, extended to 0.93A resolution and refined to a crystallographic R-factor of, 9.7%. The final model included all 310 amino acid residues, one disulfide, bond, 679 water molecules and five calcium ions. Although Sph is a, mesophilic subtilisin, its amino acid sequence is similar to that of the, psychrophilic subtilisins, which suggests that the crystal structure of, these subtilisins is very similar.The presence of five calcium ions bound, to a subtilisin molecule, as found here for Sph, has not been reported for, the subtilisin superfamily. None of these calcium-binding sites correlates, with the well-known high-affinity calcium-binding site (site I or site A), and only one site has been described previously. This calcium-binding, pattern suggests that a reduction in the flexibility of the surface loops, of Sph by calcium binding may be responsible for its adaptation to, mesophilic organisms.
About this StructureAbout this Structure
1EA7 is a Single protein structure of sequence from Lysinibacillus sphaericus with CA and S as ligands. Structure known Active Site: 1. Full crystallographic information is available from OCA.
ReferenceReference
The 0.93A crystal structure of sphericase: a calcium-loaded serine protease from Bacillus sphaericus., Almog O, Gonzalez A, Klein D, Greenblatt HM, Braun S, Shoham G, J Mol Biol. 2003 Oct 3;332(5):1071-82. PMID:14499610
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