title: SufB intein of Mycobacterium tuberculosis as a sensor for oxidative and nitrosative stresses.
abstract: Inteins are mobile genetic elements that self-splice at the protein level. Mycobacteria have inteins inserted into several important genes, including those corresponding to the iron-sulfur cluster assembly protein SufB. Curiously, the SufB inteins are found primarily in mycobacterial species that are potential human pathogens. Here we discovered an exceptional sensitivity of Mycobacterium tuberculosis SufB intein splicing to oxidative and nitrosative stresses when expressed in Escherichia coli. This effect results from predisposition of the intein's catalytic cysteine residues to oxidative and nitrosative modifications. Experiments with a fluorescent reporter system revealed that reactive oxygen species and reactive nitrogen species inhibit SufB extein ligation by forcing either precursor accumulation or N-terminal cleavage. We propose that splicing inhibition is an immediate, posttranslational regulatory response that can be either reversible, by inducing precursor accumulation, or irreversible, by inducing N-terminal cleavage, which may potentially channel mycobacteria into dormancy under extreme oxidative and nitrosative stresses.
authors.affiliation: Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY 12222;
authors.forename: Natalya I
authors.initials: NI
authors.lastname: Topilina
authors.affiliation: Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY 12222;
authors.forename: Cathleen M
authors.initials: CM
authors.lastname: Green
authors.affiliation: Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY 12222;
authors.forename: Pradeepa
authors.initials: P
authors.lastname: Jayachandran
authors.affiliation: Department of Biomedical Sciences, University at Albany, Albany, NY 12222;
authors.forename: Danielle S
authors.initials: DS
authors.lastname: Kelley
authors.affiliation: Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY 12222;
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Stanger
authors.affiliation: Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY 12222;
authors.forename: Carol Lyn
authors.initials: CL
authors.lastname: Piazza
authors.affiliation: School of Biotechnology and Kalinga Institute of Medical Sciences, Kalinga Institute of Industrial Technology University, Bhubaneswar, India 751024.
authors.forename: Sasmita
authors.initials: S
authors.lastname: Nayak
authors.affiliation: Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY 12222; Department of Biomedical Sciences, University at Albany, Albany, NY 12222; mbelfort@albany.edu.
authors.forename: Marlene
authors.initials: M
authors.lastname: Belfort
mesh_terms: D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002384:Catalysis; D003198:Computer Simulation; D003545:Cysteine / Q000737:chemistry; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D047668:Inteins; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000378:metabolism; D009584:Nitrogen / Q000737:chemistry; D018384:Oxidative Stress; D010100:Oxygen / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D019154:Protein Splicing; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
chemical_list: D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C498860:SufB protein, E coli; D003545:Cysteine; D009584:Nitrogen; D010100:Oxygen
keywords: [Fe-S] biogenesis; controllable protein splicing; cysteine chemistry; intein function; posttranslational regulation