This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.

Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.


1lnb

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
-
[[Image:1lnb.jpg|left|200px]]
+
{{Seed}}
 +
[[Image:1lnb.png|left|200px]]
<!--
<!--
Line 9: Line 10:
{{STRUCTURE_1lnb| PDB=1lnb | SCENE= }}
{{STRUCTURE_1lnb| PDB=1lnb | SCENE= }}
-
'''A STRUCTURAL ANALYSIS OF METAL SUBSTITUTIONS IN THERMOLYSIN'''
+
===A STRUCTURAL ANALYSIS OF METAL SUBSTITUTIONS IN THERMOLYSIN===
-
==Overview==
+
<!--
-
Native thermolysin binds a single catalytically essential zinc ion that is tetrahedrally coordinated by three protein ligands and a water molecule. During catalysis the zinc ligation is thought to change from fourfold to fivefold. Substitution of the active-site zinc with Cd2+, Mn2+, Fe2+, and Co2+ alters the catalytic activity (Holmquist B, Vallee BL, 1974, J Biol Chem 249:4601-4607). Excess zinc inhibits the enzyme. To investigate the structural basis of these changes in activity, we have determined the structures of a series of metal-substituted thermolysins at 1.7-1.9 A resolution. The structure of the Co(2+)-substituted enzyme is shown to be very similar to that of wild type except that two solvent molecules are liganded to the metal at positions that are thought to be occupied by the two oxygens of the hydrated scissile peptide in the transition state. Thus, the enhanced activity toward some substrates of the cobalt-relative to the zinc-substituted enzyme may be due to enhanced stabilization of the transition state. The ability of Zn2+ and Co2+ to accept tetrahedral coordination in the Michaelis complex, as well as fivefold coordination in the transition state, may also contribute to their effectiveness in catalysis. The Cd(2+)- and Mn(2+)-substituted thermolysins display conformational changes that disrupt the active site to varying degrees and could explain the associated reduction of activity. The conformational changes involve not only the essential catalytic residue, Glu 143, but also concerted side-chain rotations in the adjacent residues Met 120 and Leu 144. Some of these side-chain movements are similar to adjustments that have been observed previously in association with the "hinge-bending" motion that is presumed to occur during catalysis by the zinc endoproteases. In the presence of excess zinc, a second zinc ion is observed to bind at His 231 within 3.2 A of the zinc bound to native thermolysin, explaining the inhibitory effect.
+
The line below this paragraph, {{ABSTRACT_PUBMED_8535232}}, adds the Publication Abstract to the page
 +
(as it appears on PubMed at http://www.pubmed.gov), where 8535232 is the PubMed ID number.
 +
-->
 +
{{ABSTRACT_PUBMED_8535232}}
==About this Structure==
==About this Structure==
Line 26: Line 30:
[[Category: Juers, D.]]
[[Category: Juers, D.]]
[[Category: Matthews, B W.]]
[[Category: Matthews, B W.]]
-
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Apr 30 13:54:15 2008''
+
 
 +
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jul 2 21:29:23 2008''

Revision as of 18:29, 2 July 2008

Image:1lnb.png

Template:STRUCTURE 1lnb

A STRUCTURAL ANALYSIS OF METAL SUBSTITUTIONS IN THERMOLYSIN

Template:ABSTRACT PUBMED 8535232

About this Structure

1LNB is a Single protein structure. Full crystallographic information is available from OCA.

Reference

Structural analysis of zinc substitutions in the active site of thermolysin., Holland DR, Hausrath AC, Juers D, Matthews BW, Protein Sci. 1995 Oct;4(10):1955-65. PMID:8535232

Page seeded by OCA on Wed Jul 2 21:29:23 2008

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1lnb"
Personal tools