Structural highlights
Function
[SACY_BACSU] In the presence of sucrose, SacY is activated and prevents premature termination of transcription by binding to a RNA-antiterminator (RAT) sequence (partially overlapping with the terminator sequence) located upstream of the sacB gene. Formation of the SacY-RAT complex prevents alternative formation of the terminator, allowing transcription of the sacB gene. In the absence of sucrose, inhibition of SacY activity by SacX leads to termination of transcription.[1]
Evolutionary Conservation
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Publication Abstract from PubMed
SacY is the prototype of a family of regulatory proteins able to prevent transcription termination. It interacts with a 29 nucleotide RNA sequence able to fold into a stem-loop structure and partially overlapping with a terminator sequence located in the 5' leader mRNA region of the gene it controls. We show here that the N-terminal fragment of SacY, SacY(1-55), and the corresponding fragments of other members of the family have antiterminator activities with efficiency and specificity identical to those of the full-length proteins. In vitro, this activity correlates with the specific affinity of SacY(1-55) for its RNA target. UV melting experiments demonstrate that SacY(1-55) binding stabilizes the RNA target structure. The NMR solution structure of SacY(1-55) is very similar to that obtained in the crystal (van Tilbeurgh et al., 1997): the peptide is folded as a symmetrical dimer without any structural homology with other RNA-binding domains yet characterized. According to a preliminary NMR analysis of the SacY(1-55)-RNA complex, the protein dimer is not disrupted upon RNA binding and several residues implicated in RNA recognition are located at the edge of the dimer interface. This suggests a new mode of protein-RNA interaction.
From genetic to structural characterization of a new class of RNA-binding domain within the SacY/BglG family of antiterminator proteins.,Manival X, Yang Y, Strub MP, Kochoyan M, Steinmetz M, Aymerich S EMBO J. 1997 Aug 15;16(16):5019-29. PMID:9305643[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Tortosa P, Le Coq D. A ribonucleic antiterminator sequence (RAT) and a distant palindrome are both involved in sucrose induction of the Bacillus subtilis sacXY regulatory operon. Microbiology. 1995 Nov;141 ( Pt 11):2921-7. PMID:8535520
- ↑ Manival X, Yang Y, Strub MP, Kochoyan M, Steinmetz M, Aymerich S. From genetic to structural characterization of a new class of RNA-binding domain within the SacY/BglG family of antiterminator proteins. EMBO J. 1997 Aug 15;16(16):5019-29. PMID:9305643 doi:10.1093/emboj/16.16.5019
