Linked Life Data

2838076

Source:http://linkedlifedata.com/resource/pubmed/id/2838076

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
1988-8-1
pubmed:abstractText
By freezing CO-bound cytochrome c oxidase at cryogenic temperatures, we have been able to cryotrap metastable intermediates of photodissociation. The differences in the resonance Raman spectrum between these intermediates and ligand-free reduced cytochrome oxidase at cryogenic temperatures are the same as those between the phototransient and the fully reduced preparation detected with 10-ns excitation at room temperature. The largest difference occurs in the iron-histidine stretching mode of cytochrome a3, which shifts by up to 8 cm-1 to higher frequency in the photoproduct. At 4 K the iron-histidine mode displays two unrelaxed frequencies in the photoproduct, which we attribute to two different unrelaxed structures of the heme pocket. The frequencies and intensities of the lines in the resonance Raman spectrum are sensitive to the incident laser power density in both the ligand-free fully reduced preparation and the photoproduct even at 4 K. At 77 K the carbonyl stretching mode of the formyl group in cytochrome a32+ is especially sensitive to laser power, displaying two frequencies-1666 cm-1 at low-flux density and 1674 cm-1 at high-flux density. These frequencies may reflect a change in conformation of the formyl group or a change in its interaction with the protein such as in hydrogen bonding to the carbonyl of the formyl group. The absence of immediate relaxation of the CO photoproduct must be considered when one studies the structure and kinetics of the O2 intermediates that are formed in triple trapping and flow-flash experiments following photodissociation of the CO-bound enzyme.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2496-502
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Photodissociated cytochrome c oxidase: cryotrapped metastable intermediates.
pubmed:affiliation
AT & T Bell Laboratories, New Jersey 07974.
pubmed:publicationType
Journal Article