Linked Life Data

21524102

Source:http://linkedlifedata.com/resource/pubmed/id/21524102

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
2011-5-24
pubmed:abstractText
Bacterial cytochrome c peroxidase (CcP) enzymes are diheme redox proteins that reduce hydrogen peroxide to water. They are canonically characterized by a peroxidatic (called L, for "low reduction potential") active site heme and a secondary heme (H, for "high reduction potential") associated with electron transfer, and an enzymatic activity that exists only when the H-heme is prereduced to the Fe(II) oxidation state. The prereduction step results in a conformational change at the active site itself, where a histidine-bearing loop will adopt an "open" conformation allowing hydrogen peroxide to bind to the Fe(III) of the L-heme. Notably, the enzyme from Nitrosomonas europaea does not require prereduction. Previously, we have shown that protein film voltammetry (PFV) is a highly useful tool for distinguishing the electrocatalytic mechanisms of the Nitromonas type of enzyme from other CcPs. Here, we apply PFV to the recently described enzyme from Geobacter sulfurreducens and the Geobacter S134P/V135K double mutant, which have been shown to be similar to members of the canonical subclass of peroxidases and the Nitrosomonas subclass of enzymes, respectively. Here we find that the wild-type Geobacter CcP is indeed similar electrochemically to the bacterial CcPs that require reductive activation, yet the S134P/V135K mutant shows two phases of electrocatalysis: one that is low in potential, like that of the wild-type enzyme, and a second, higher-potential phase that has a potential dependent upon substrate binding and pH yet is at a potential that is very similar to that of the H-heme. These findings are interpreted in terms of a model in which rate-limiting intraprotein electron transfer governs the catalytic performance of the S134P/V135K enzyme.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1520-4995
pubmed:author
pubmed:issnType
Electronic
pubmed:day
31
pubmed:volume
50
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4513-20
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Geobacter sulfurreducens cytochrome c peroxidases: electrochemical classification of catalytic mechanisms.
pubmed:affiliation
Department of Chemistry, Boston University, Boston, MA 02215, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural