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Photophysics and photochemistry of horseradish peroxidase A2 upon ultraviolet illumination

2007-03Journal article Open Access
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dc.contributor.authorNeves-Petersen, Maria Teresa
dc.contributor.authorKlitgaard, Soren
dc.contributor.authorLeitao Carvalho, Ana Sofia
dc.contributor.authorPetersen, Steffen B.
dc.contributor.authorde Barros, Maria Raquel Aires
dc.contributor.authorMelo, Eduardo
dc.date.accessioned2018-12-07T14:53:45Z
dc.date.available2018-12-07T14:53:45Z
dc.date.issued2007-03
dc.description.abstractDetailed analysis of the effects of ultraviolet (UV) and blue light illumination of horseradish peroxidase A2, a heme-containing enzyme that reduces H2O2 to oxidize organic and inorganic compounds, is presented. The effects of increasing illumination time on the protein's enzymatic activity, Reinheitzahl value,. fluorescence emission,. fluorescence lifetime distribution,. fluorescence mean lifetime, and heme absorption are reported. UV illumination leads to an exponential decay of the enzyme activity followed by changes in heme group absorption. Longer UV illumination time leads to lower T-m values as well as helical content loss. Prolonged UV illumination and heme irradiation at 403 nm has a pronounced effect on the. fluorescence quantum yield correlated with changes in the prosthetic group pocket, leading to a pronounced decrease in the heme's Soret absorbance band. Analysis of the picosecond-resolved. fluorescence emission of horseradish peroxidase A2 with streak camera shows that UV illumination induces an exponential change in the preexponential factors distribution associated to the protein's. fluorescence lifetimes, leading to an exponential increase of the mean. fluorescence lifetime. Illumination of aromatic residues and of the heme group leads to changes indicative of heme leaving the molecule and/or that photoinduced chemical changes occur in the heme moiety. Our studies bring new insight into light-induced reactions in proteins. We show how streak camera technology can be of outstanding value to follow such ultrafast processes and how streak camera data can be correlated with protein structural changes.
dc.identifier.doi10.1529/biophysj.106.095455
dc.identifier.issn0006-3495
dc.identifier.urihttp://hdl.handle.net/10400.1/11670
dc.language.isoeng
dc.peerreviewedyes
dc.publisherBiophysical Society
dc.subjectAromatic-Amino-Acids
dc.subjectCytochrome-C Peroxidase
dc.subjectExcited-State Chemistry
dc.subjectUnusual Fluorescence Behavior
dc.subjectDilute Aqueous-Solution
dc.subjectTryptophan Fluorescence
dc.subjectCircular-Dichroism
dc.subjectHydrated Electron
dc.subjectGlobal Analysis
dc.subjectInactivation
dc.titlePhotophysics and photochemistry of horseradish peroxidase A2 upon ultraviolet illumination
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage2027
oaire.citation.issue6
oaire.citation.startPage2016
oaire.citation.titleBiophysical Journal
oaire.citation.volume92
person.familyNamePinho Melo
person.givenNameEduardo
person.identifier1443188
person.identifier.ciencia-id3C1C-C10C-1510
person.identifier.orcid0000-0002-0974-8977
person.identifier.scopus-author-id35566177900
rcaap.rightsopenAccess
rcaap.typearticle
relation.isAuthorOfPublication5fa1895f-5577-4652-961a-886ec9bf41b1
relation.isAuthorOfPublication.latestForDiscovery5fa1895f-5577-4652-961a-886ec9bf41b1

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