| Impact of phosphorylation and phosphorylation-null mutants on the activity and deamination specificity of activation-induced cytidine deaminase. | |
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MedLine Citation:
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PMID: 18417471 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Activation-induced cytidine deaminase (AID) initiates somatic hypermutation and class switch recombination in B cells by deaminating C --> U on transcribed DNA. Here we analyze the role of phosphorylation and phosphorylation-null mutants on the biochemical behavior of AID, including enzyme specific activity, processivity, deamination spectra, deamination motif specificity, and transcription-dependent deamination in the presence and absence of RPA. We show that a small fraction of recombinant human AID expressed in Sf9 insect cells is phosphorylated at previously identified residues Ser(38) and Thr(27) and also at Ser(41) and Ser(43). S43P AID has been identified in a patient with hyper-IgM immunodeficiency syndrome. Ser-substituted phosphorylation-null mutants (S38A, S41A, S43A, and S43P) exhibit wild type (WT) activity on single-stranded DNA. Deamination of transcribed double-stranded DNA is similar for WT and mutant AID and occurs with or without RPA. Although WT and AID mutants catalyze processive deamination favoring canonical WRC hot spot motifs (where W represents A/T and R is A/G), their deamination spectra differ significantly. The differences between the WT and AID mutants appear to be caused by the replacement of Ser as opposed to an absence of phosphorylation. The spectral differences reflect a marked change in deamination efficiencies in two motifs, GGC and AGC, which are preferred by mutant AID but disfavored by WT AID. Both motifs occur with exceptionally high frequency in human switch regions, suggesting a possible relationship between AID deamination specificity and a loss of antibody diversification. |
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Authors:
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Phuong Pham; Marcus B Smolka; Peter Calabrese; Alice Landolph; Ke Zhang; Huilin Zhou; Myron F Goodman |
Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't Date: 2008-04-16 |
Journal Detail:
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Title: The Journal of biological chemistry Volume: 283 ISSN: 0021-9258 ISO Abbreviation: J. Biol. Chem. Publication Date: 2008 Jun |
Date Detail:
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Created Date: 2008-06-16 Completed Date: 2008-07-25 Revised Date: 2011-01-19 |
Medline Journal Info:
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Nlm Unique ID: 2985121R Medline TA: J Biol Chem Country: United States |
Other Details:
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Languages: eng Pagination: 17428-39 Citation Subset: IM |
Affiliation:
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Department of Biological Sciences, University of Southern California, Los Angeles, California 90089-2910, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Amino Acid Motifs Animals Cell Line Cytidine Deaminase / genetics*, metabolism* DNA / chemistry, metabolism DNA Mutational Analysis DNA, Single-Stranded / chemistry Humans Insects Mass Spectrometry / methods Models, Biological Mutation* Phosphorylation Serine / chemistry Transcription, Genetic |
| Grant Support | |
ID/Acronym/Agency:
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ES013192/ES/NIEHS NIH HHS; GM080469/GM/NIGMS NIH HHS; R01 GM080469-02/GM/NIGMS NIH HHS; R01 GM080469-05/GM/NIGMS NIH HHS; R37GM21422/GM/NIGMS NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/DNA, Single-Stranded; 56-45-1/Serine; 9007-49-2/DNA; EC 3.5.4.-/AICDA (activation-induced cytidine deaminase); EC 3.5.4.5/Cytidine Deaminase |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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