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Regulation of translocation polarity by helicase domain 1 in SF2B helicases
Author(s) -
Pugh Robert A,
Wu Colin G,
Spies Maria
Publication year - 2012
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2011.412
Subject(s) - biology , helicase , chromosomal translocation , polarity (international relations) , microbiology and biotechnology , rna helicase a , domain (mathematical analysis) , genetics , computational biology , gene , cell , rna , mathematical analysis , mathematics
Structurally similar superfamily I (SF1) and II (SF2) helicases translocate on single‐stranded DNA (ssDNA) with defined polarity either in the 5′–3′ or in the 3′–5′ direction. Both 5′–3′ and 3′–5′ translocating helicases contain the same motor core comprising two RecA‐like folds. SF1 helicases of opposite polarity bind ssDNA with the same orientation, and translocate in opposite directions by employing a reverse sequence of the conformational changes within the motor domains. Here, using proteolytic DNA and mutational analysis, we have determined that SF2B helicases bind ssDNA with the same orientation as their 3′–5′ counterparts. Further, 5′–3′ translocation polarity requires conserved residues in HD1 and the FeS cluster containing domain. Finally, we propose the FeS cluster‐containing domain also provides a wedge‐like feature that is the point of duplex separation during unwinding.