7tln
From Proteopedia
(New page: 200px<br /><applet load="7tln" size="450" color="white" frame="true" align="right" spinBox="true" caption="7tln, resolution 2.3Å" /> '''STRUCTURAL ANALYSIS O...) |
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| - | [[Image:7tln.gif|left|200px]]<br /><applet load="7tln" size=" | + | [[Image:7tln.gif|left|200px]]<br /><applet load="7tln" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="7tln, resolution 2.3Å" /> | caption="7tln, resolution 2.3Å" /> | ||
'''STRUCTURAL ANALYSIS OF THE INHIBITION OF THERMOLYSIN BY AN ACTIVE-SITE-DIRECTED IRREVERSIBLE INHIBITOR'''<br /> | '''STRUCTURAL ANALYSIS OF THE INHIBITION OF THERMOLYSIN BY AN ACTIVE-SITE-DIRECTED IRREVERSIBLE INHIBITOR'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The mode of binding of the irreversible thermolysin inhibitor | + | The mode of binding of the irreversible thermolysin inhibitor ClCH2CO-DL-(N-OH)Leu-OCH3 [Rasnick, D., & Powers, J.C. (1978) Biochemistry 17, 4363-4369] has been determined by X-ray crystallography at a resolution of 2.3 A and the structure of the covalent complex refined to give a crystallographic residual of 17.0%. This is the first such structural study of an active-site-directed covalent complex of a zinc protease. As anticipated by Rasnick and Powers, the inhibitor alkylates Glu-143 in the thermolysin active site, and the hydroxamic acid moiety coordinates the zinc ion. The formation of the covalent complex is associated with a significant shift in a segment of the polypeptide backbone in the vicinity of the active site. This conformational adjustment appears to be necessary to relieve steric hindrance which would otherwise prevent alkylation of Glu-143. It is suggested that this steric hindrance, which occurs for thermolysin but would not be expected for carboxypeptidase A, accounts for the previously inexplicable difference in reactivity of these two metalloproteases toward N-haloacetyl amino acids. The relevance of this steric hindrance to the mechanism of catalysis is discussed. In agreement with previous results [Kester, W. R., & Matthews, B. W. (1977) Biochemistry 16, 2506-2516], it appears that steric hindrance prevents the direct attack of Glu-143 on the carbonyl carbon of an extended substrate, therefore ruling out the anhydride pathway in thermolysin-catalyzed hydrolysis of polypeptide substrates and their ester analogues. |
==About this Structure== | ==About this Structure== | ||
| - | 7TLN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_thermoproteolyticus Bacillus thermoproteolyticus] with CA, ZN and INC as [http://en.wikipedia.org/wiki/ligands ligands]. This structure | + | 7TLN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_thermoproteolyticus Bacillus thermoproteolyticus] with <scene name='pdbligand=CA:'>CA</scene>, <scene name='pdbligand=ZN:'>ZN</scene> and <scene name='pdbligand=INC:'>INC</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. This structure supersedes the now removed PDB entry 6TLN. Active as [http://en.wikipedia.org/wiki/Thermolysin Thermolysin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.24.27 3.4.24.27] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7TLN OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Thermolysin]] | [[Category: Thermolysin]] | ||
| - | [[Category: Holmes, M | + | [[Category: Holmes, M A.]] |
| - | [[Category: Matthews, B | + | [[Category: Matthews, B W.]] |
| - | [[Category: Tronrud, D | + | [[Category: Tronrud, D E.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: INC]] | [[Category: INC]] | ||
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[[Category: hydrolase (metalloproteinase)]] | [[Category: hydrolase (metalloproteinase)]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 19:17:38 2008'' |
Revision as of 17:17, 21 February 2008
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STRUCTURAL ANALYSIS OF THE INHIBITION OF THERMOLYSIN BY AN ACTIVE-SITE-DIRECTED IRREVERSIBLE INHIBITOR
Overview
The mode of binding of the irreversible thermolysin inhibitor ClCH2CO-DL-(N-OH)Leu-OCH3 [Rasnick, D., & Powers, J.C. (1978) Biochemistry 17, 4363-4369] has been determined by X-ray crystallography at a resolution of 2.3 A and the structure of the covalent complex refined to give a crystallographic residual of 17.0%. This is the first such structural study of an active-site-directed covalent complex of a zinc protease. As anticipated by Rasnick and Powers, the inhibitor alkylates Glu-143 in the thermolysin active site, and the hydroxamic acid moiety coordinates the zinc ion. The formation of the covalent complex is associated with a significant shift in a segment of the polypeptide backbone in the vicinity of the active site. This conformational adjustment appears to be necessary to relieve steric hindrance which would otherwise prevent alkylation of Glu-143. It is suggested that this steric hindrance, which occurs for thermolysin but would not be expected for carboxypeptidase A, accounts for the previously inexplicable difference in reactivity of these two metalloproteases toward N-haloacetyl amino acids. The relevance of this steric hindrance to the mechanism of catalysis is discussed. In agreement with previous results [Kester, W. R., & Matthews, B. W. (1977) Biochemistry 16, 2506-2516], it appears that steric hindrance prevents the direct attack of Glu-143 on the carbonyl carbon of an extended substrate, therefore ruling out the anhydride pathway in thermolysin-catalyzed hydrolysis of polypeptide substrates and their ester analogues.
About this Structure
7TLN is a Single protein structure of sequence from Bacillus thermoproteolyticus with , and as ligands. This structure supersedes the now removed PDB entry 6TLN. Active as Thermolysin, with EC number 3.4.24.27 Full crystallographic information is available from OCA.
Reference
Structural analysis of the inhibition of thermolysin by an active-site-directed irreversible inhibitor., Holmes MA, Tronrud DE, Matthews BW, Biochemistry. 1983 Jan 4;22(1):236-40. PMID:6830761
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