From Proteopedia
(Difference between revisions)
proteopedia linkproteopedia link
|
|
| Line 1: |
Line 1: |
| - | [[Image:1stq.jpg|left|200px]] | + | {{Seed}} |
| | + | [[Image:1stq.png|left|200px]] |
| | | | |
| | <!-- | | <!-- |
| Line 9: |
Line 10: |
| | {{STRUCTURE_1stq| PDB=1stq | SCENE= }} | | {{STRUCTURE_1stq| PDB=1stq | SCENE= }} |
| | | | |
| - | '''Cyrstal Structure of Cytochrome c Peroxidase Mutant: CcPK2M3'''
| + | ===Cyrstal Structure of Cytochrome c Peroxidase Mutant: CcPK2M3=== |
| | | | |
| | | | |
| - | ==Overview==
| + | <!-- |
| - | Previously a K(+)-binding site, analogous to that found in ascorbate peroxidase (APX), was engineered into cytochrome c peroxidase (CcP) to test the hypothesis that the bound K(+) influences the stability of the Trp191 cation radical formed during the CcP catalytic cycle (Bonagura et al., (1996) Biochemistry 35, 6107 and Bonagura et al., (1999) Biochemistry 38, 5528). Characterization of this mutant, designated CcPK2, showed that the stability of the Trp191 cation radical is dependent on the occupancy of the engineered K(+) site and that the Trp191 radical was much less stable in this mutant than in wild-type CcP. The mutations Met230Leu, Met231Gln, and Met172Ser have now been constructed on the CcPK2 mutant template to test if the Met residues also contribute to the stabilization of the Trp191 cation radical. Crystal structures show that the mutations affect only the local structure near the sites of mutation. Removal of these electronegative residues located less than 8 A from the Trp radical results in a further destabilization of the Trp radical. The characteristic EPR signal associated with the Trp radical is significantly narrowed and is characteristic of a tyrosine radical signal. Double-mixing stopped-flow experiments, where the delay time between the formation of CcP compound I and its mixing with horse heart ferrocytochrome c is varied, show that the stability of the Trp radical decreases as the Met residues are removed from the proximal cavity. When taken together, these results demonstrate a strong correlation between the experimentally determined stability of the Trp191 radical, the enzyme activity, and the calculated electrostatic stabilization of the Trp191 radical.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_15236591}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 15236591 is the PubMed ID number. |
| | + | --> |
| | + | {{ABSTRACT_PUBMED_15236591}} |
| | | | |
| | ==About this Structure== | | ==About this Structure== |
| Line 30: |
Line 34: |
| | [[Category: Haem peroxidase]] | | [[Category: Haem peroxidase]] |
| | [[Category: Heme peroxidase]] | | [[Category: Heme peroxidase]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 09:07:37 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 01:44:02 2008'' |
Revision as of 22:44, 27 July 2008
Template:STRUCTURE 1stq
Cyrstal Structure of Cytochrome c Peroxidase Mutant: CcPK2M3
Template:ABSTRACT PUBMED 15236591
About this Structure
1STQ is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
Reference
Electrostatic control of the tryptophan radical in cytochrome c peroxidase., Barrows TP, Bhaskar B, Poulos TL, Biochemistry. 2004 Jul 13;43(27):8826-34. PMID:15236591
Page seeded by OCA on Mon Jul 28 01:44:02 2008
