title: Parallel dimerization of a PrrC-anticodon nuclease region implicated in tRNALys recognition.
abstract: The optional Escherichia coli restriction tRNase PrrC represents a family of potential antiviral devices widespread among bacteria. PrrC comprises a functional C-domain of unknown structure and regulatory ABC/ATPase-like N-domain. The possible involvement of a C-domain sequence in tRNA(Lys) recognition was investigated using a matching end-protected 11-meric peptide. This mimic, termed here LARP (Lys-anticodon recognizing peptide) UV-cross-linked tRNA(Lys) anticodon stem-loop (ASL) analogs and inhibited their PrrC-catalyzed cleavage. Trimming LARP or introducing in it inactivating PrrC missense mutations impaired these activities. LARP appeared to mimic its matching protein sequence in ability to dimerize in parallel, as inferred from the following results. First, tethering Cys to the amino- or carboxy-end of LARP dramatically enhanced the ASL-cross-linking and PrrC-inhibiting activities under suitable redox conditions. Second, Cys-substitutions in a C-domain region containing the sequence corresponding to LARP elicited specific intersubunit cross-links. The parallel dimerization of PrrC's C-domains and expected head-to-tail dimerization of its N-domains further suggest that the NTPase and tRNA(Lys)-binding sites of PrrC arise during distinct assembly stages of its dimer of dimers form.
authors.affiliation: Department of Biochemistry, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Daniel
authors.initials: D
authors.lastname: Klaiman
authors.forename: Michal
authors.initials: M
authors.lastname: Amitsur
authors.forename: Shani
authors.initials: S
authors.lastname: Blanga-Kanfi
authors.forename: Michal
authors.initials: M
authors.lastname: Chai
authors.forename: Darrell R
authors.initials: DR
authors.lastname: Davis
authors.forename: Gabriel
authors.initials: G
authors.lastname: Kaufmann
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D003545:Cysteine / Q000737:chemistry; D019281:Dimerization; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D018716:Molecular Mimicry; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009842:Oligopeptides / Q000737:chemistry / Q000494:pharmacology; D010084:Oxidation-Reduction; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry; D012357:RNA, Transfer, Lys / Q000737:chemistry*; D012260:Ribonucleases / Q000737:chemistry* / Q000378:metabolism; D016415:Sequence Alignment; D014466:Ultraviolet Rays
chemical_list: C522720:ASL-3 nucleotide; D029968:Escherichia coli Proteins; C522719:LARP peptide; D009842:Oligopeptides; D021122:Protein Subunits; D012357:RNA, Transfer, Lys; C084965:PrrC protein, E coli; D012260:Ribonucleases; D003545:Cysteine