5GQO

Structure of the second Single Stranded DNA Binding protein (SSBb) from Mycobacterium smegmatis

Summary for 5GQO

• Entry DOI: 10.2210/pdb5gqo/pdb
• Descriptor: Single-stranded DNA-binding protein, CALCIUM ION (3 entities in total)
• Functional Keywords: ob fold, inter-subunit clamp, paralogous ssb, variability, quaternary structure, dna binding protein
• Biological source: Mycobacterium smegmatis (strain ATCC 700084 / mc(2)155)
• Total number of polymer chains: 2
• Total formula weight: 41495.50

Authors

Singh, A.,Varshney, U.,Vijayan, M. (deposition date: 2016-08-08, release date: 2016-10-12, Last modification date: 2023-11-08)

Primary citation

Singh, A.,Varshney, U.,Vijayan, M.
Structure of the second Single Stranded DNA Binding protein (SSBb) from Mycobacterium smegmatis.
J. Struct. Biol., 196:448-454, 2016

PubMed Abstract: All mycobacteria with sequenced genomes, except M. leprae, have a second Single Stranded DNA Binding protein (SSBb) in addition to the canonical one (SSBa). This paralogue from M. smegmatis (MsSSBb) has been cloned, expressed and purified. The protein, which is probably involved in stress response, has been crystallized and X-ray analyzed in the first structure elucidation of a mycobacterial SSBb. In spite of the low sequence identity between SSBas and SSBbs in mycobacteria, the tertiary and quaternary structure of the DNA binding domain of MsSSBb is similar to that observed in mycobacterial SSBas. In particular, the quaternary structure is 'clamped' using a C-terminal stretch of the N-domain, which endows the tetrameric molecule with additional stability and its characteristic shape. Comparison involving available, rather limited, structural data on SSBbs from other sources, appears to suggest that SSBbs could exhibit higher structural variability than SSBas do.

PubMed: 27659385
DOI: 10.1016/j.jsb.2016.09.012

Experimental method

X-RAY DIFFRACTION (2.5 Å)