| Detection of Distinct α-Helical Rearrangements of CPD Photolyase upon Substrate Binding by FTIR Spectroscopy. | |
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MedLine Citation:
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PMID: 23331252 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Photolyases (PHRs) utilize near UV/blue light to specifically repair the major photoproducts (PPs) of UV-induced damaged DNA by utilizing near UV/blue light. The cyclobutane pyrimidine dimer (CPD)-PHR from Escherichia coli binds flavin adenine dinucleotide (FAD) as a cofactor and 5,10-methenyltetrahydrofolate (MTHF) as a light harvesting pigment, and specifically repairs CPD lesions. By comparison, a second photolyase known as (6-4) PHR present in a range of higher organisms uniquely repairs (6-4)PPs. To understand the repair mechanism and the substrate specificity that distinguish CPD-PHR from (6-4) PHR, we applied Fourier transform infrared (FTIR) spectroscopy to bacterial CPD-PHR in the presence or absence of a well-defined DNA substrate, while we have studied on vertebrate (6-4) PHR. PHRs show light-induce reduction of FAD, and photorepair by CPD-PHR involves electron transfer from the photoexcited FADH- to the damaged DNA for cleaving the dimers to maintain the DNA's integrity. Here, we measured difference FTIR spectra for the photoactivation and DNA photorepair processes of CPD-PHR. We identified light-dependent signals only in the presence of substrate. The signals, presumably arising from a protonated carboxylic acid or the DNA substrate, implicate the occurrence of potential protein and substrate dynamics of the repair process. Deuterium exchange FTIR measurements of CPD-PHR highlights the potential differences in the photoactivation and photorepair mechanism in comparison to (6-4) PHR. While CPD and (6-4) PHRs appear to exhibit similar overall structures, our studies indicate that the conformational changes, especially α-helices perturbations, initiated within these enzymes upon binding their respective DNA substrates are quite diverse. |
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Authors:
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I M Mahaputra Wijaya; Yu Zhang; Tatsuya Iwata; Junpei Yamamoto; Kenichi Hitomi; Shigenori Iwai; Elizabeth Dickinson Getzoff; Hideki Kandori |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2013-1-21 |
Journal Detail:
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Title: Biochemistry Volume: - ISSN: 1520-4995 ISO Abbreviation: Biochemistry Publication Date: 2013 Jan |
Date Detail:
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Created Date: 2013-1-21 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0370623 Medline TA: Biochemistry Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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