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Characterization of DNA strand transfer promoted by Mycobacterium smegmatis RecA reveals functional diversity with Mycobacterium tuberculosis RecA.
Biochemistry 2003; 42(23):7216-25B

Abstract

The RecA-like proteins constitute a group of DNA strand transfer proteins ubiquitous in eubacteria, eukarya, and archaea. However, the functional relationship among RecA proteins is poorly understood. For instance, Mycobacterium tuberculosis RecA is synthesized as a large precursor, which undergoes an unusual protein-splicing reaction to generate an active form. Whereas the precursor was inactive, the active form promoted DNA strand transfer less efficiently compared to EcRecA. Furthermore, gene disruption studies have indicated that the frequencies of allele exchange are relatively lower in Mycobacterium tuberculosis compared to Mycobacterium smegmatis. The mechanistic basis and the factors that contribute to differences in allele exchange remain to be understood. Here, we show that the extent of DNA strand transfer promoted by the M. smegmatis RecA in vitro differs significantly from that of M. tuberculosis RecA. Importantly, M. smegmatis RecA by itself was unable to promote strand transfer, but cognate or noncognate SSBs rendered it efficient even when added prior to RecA. In the presence of SSB, MsRecA or MtRecA catalyzed strand transfer between ssDNA and varying lengths of linear duplex DNA with distinctly different pH profiles. The factors that were able to suppress the formation of DNA networks greatly stimulated strand transfer reactions promoted by MsRecA or MtRecA. Although the rate and pH profiles of dATP hydrolysis catalyzed by MtRecA and MsRecA were similar, only MsRecA was able to couple dATP hydrolysis to DNA strand transfer. Together, these results provide insights into the functional diversity in DNA strand transfer promoted by RecA proteins of pathogenic and nonpathogenic species of mycobacteria.

Authors+Show Affiliations

Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

12795618

Citation

Ganesh, N, and K Muniyappa. "Characterization of DNA Strand Transfer Promoted By Mycobacterium Smegmatis RecA Reveals Functional Diversity With Mycobacterium Tuberculosis RecA." Biochemistry, vol. 42, no. 23, 2003, pp. 7216-25.
Ganesh N, Muniyappa K. Characterization of DNA strand transfer promoted by Mycobacterium smegmatis RecA reveals functional diversity with Mycobacterium tuberculosis RecA. Biochemistry. 2003;42(23):7216-25.
Ganesh, N., & Muniyappa, K. (2003). Characterization of DNA strand transfer promoted by Mycobacterium smegmatis RecA reveals functional diversity with Mycobacterium tuberculosis RecA. Biochemistry, 42(23), pp. 7216-25.
Ganesh N, Muniyappa K. Characterization of DNA Strand Transfer Promoted By Mycobacterium Smegmatis RecA Reveals Functional Diversity With Mycobacterium Tuberculosis RecA. Biochemistry. 2003 Jun 17;42(23):7216-25. PubMed PMID: 12795618.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Characterization of DNA strand transfer promoted by Mycobacterium smegmatis RecA reveals functional diversity with Mycobacterium tuberculosis RecA. AU - Ganesh,N, AU - Muniyappa,K, PY - 2003/6/11/pubmed PY - 2003/7/25/medline PY - 2003/6/11/entrez SP - 7216 EP - 25 JF - Biochemistry JO - Biochemistry VL - 42 IS - 23 N2 - The RecA-like proteins constitute a group of DNA strand transfer proteins ubiquitous in eubacteria, eukarya, and archaea. However, the functional relationship among RecA proteins is poorly understood. For instance, Mycobacterium tuberculosis RecA is synthesized as a large precursor, which undergoes an unusual protein-splicing reaction to generate an active form. Whereas the precursor was inactive, the active form promoted DNA strand transfer less efficiently compared to EcRecA. Furthermore, gene disruption studies have indicated that the frequencies of allele exchange are relatively lower in Mycobacterium tuberculosis compared to Mycobacterium smegmatis. The mechanistic basis and the factors that contribute to differences in allele exchange remain to be understood. Here, we show that the extent of DNA strand transfer promoted by the M. smegmatis RecA in vitro differs significantly from that of M. tuberculosis RecA. Importantly, M. smegmatis RecA by itself was unable to promote strand transfer, but cognate or noncognate SSBs rendered it efficient even when added prior to RecA. In the presence of SSB, MsRecA or MtRecA catalyzed strand transfer between ssDNA and varying lengths of linear duplex DNA with distinctly different pH profiles. The factors that were able to suppress the formation of DNA networks greatly stimulated strand transfer reactions promoted by MsRecA or MtRecA. Although the rate and pH profiles of dATP hydrolysis catalyzed by MtRecA and MsRecA were similar, only MsRecA was able to couple dATP hydrolysis to DNA strand transfer. Together, these results provide insights into the functional diversity in DNA strand transfer promoted by RecA proteins of pathogenic and nonpathogenic species of mycobacteria. SN - 0006-2960 UR - https://www.unboundmedicine.com/medline/citation/12795618/Characterization_of_DNA_strand_transfer_promoted_by_Mycobacterium_smegmatis_RecA_reveals_functional_diversity_with_Mycobacterium_tuberculosis_RecA_ L2 - https://dx.doi.org/10.1021/bi0340548 DB - PRIME DP - Unbound Medicine ER -