title: A full-length bifunctional protein involved in c-di-GMP turnover is required for long-term survival under nutrient starvation in Mycobacterium smegmatis.
abstract: The bacterial second messenger cyclic diguanosine monophosphate (c-di-GMP) plays an important role in a variety of cellular functions, including biofilm formation, alterations in the cell surface, host colonization and regulation of bacterial flagellar motility, which enable bacteria to survive changing environmental conditions. The cellular level of c-di-GMP is regulated by a balance between opposing activities of diguanylate cyclases (DGCs) and cognate phosphodiesterases (PDE-As). Here, we report the presence and importance of a protein, MSDGC-1 (an orthologue of Rv1354c in Mycobacterium tuberculosis), involved in c-di-GMP turnover in Mycobacterium smegmatis. MSDGC-1 is a multidomain protein, having GAF, GGDEF and EAL domains arranged in tandem, and exhibits both c-di-GMP synthesis and degradation activities. Most other proteins containing GGDEF and EAL domains have been demonstrated to have either DGC or PDE-A activity. Unlike other bacteria, which harbour several copies of the protein involved in c-di-GMP turnover, M. smegmatis has a single genomic copy, deletion of which severely affects long-term survival under conditions of nutrient starvation. Overexpression of MSDGC-1 alters the colony morphology and growth profile of M. smegmatis. In order to gain insights into the regulation of the c-di-GMP level, we cloned individual domains and tested their activities. We observed a loss of activity in the separated domains, indicating the importance of full-length MSDGC-1 for controlling bifunctionality.
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore-560012, India.
authors.forename: Binod K
authors.initials: BK
authors.lastname: Bharati
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore-560012, India.
authors.forename: Indra Mani
authors.initials: IM
authors.lastname: Sharma
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore-560012, India.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Kasetty
authors.affiliation: Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611-0700, USA.
authors.forename: Manish
authors.initials: M
authors.lastname: Kumar
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore-560012, India.
authors.forename: Raju
authors.initials: R
authors.lastname: Mukherjee
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore-560012, India.
authors.forename: Dipankar
authors.initials: D
authors.lastname: Chatterji
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000378:metabolism; D050296:Microbial Viability; D008969:Molecular Sequence Data; D020102:Mycobacterium smegmatis / Q000737:chemistry / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; C062025:bis(3',5')-cyclic diguanylic acid; D006152:Cyclic GMP