Structural highlights
3tka is a 1 chain structure with sequence from Escherichia coli k-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
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| Ligands: | , , , |
| Gene: | rsmH, mraW, yabC, b0082, JW0080 (Escherichia coli K-12) |
| Activity: | 16S rRNA (cytosine(1402)-N(4))-methyltransferase, with EC number 2.1.1.199 |
| Resources: | FirstGlance, OCA, RCSB, PDBsum |
Function
[RSMH_ECOLI] Specifically methylates the N4 position of cytidine in position 1402 (C1402) of 16S rRNA. In vitro, active on the assembled 30S subunit, but not naked 16S rRNA or 70S ribosomes.[1] [2]
Publication Abstract from PubMed
RsmH is a specific AdoMet-dependent methyltransferase (MTase) responsible for N(4)-methylation of C1402 in 16S rRNA and conserved in almost all species of bacteria. The methylcytidine interacts with the P-site codon of the mRNA and increases ribosomal decoding fidelity. In this study, high resolution crystal structure (2.25A) of Escherichia coli RsmH in complex with AdoMet and cytidine (the putative rRNA binding site) was determined. The structural analysis demonstrated that the complex consists of two distinct but structurally related domains: the typical MTase domain and the putative substrate recognition and binding domain. A deep pocket was found in the conserved AdoMet binding domain. It was also found that the cytidine bound far from AdoMet with the distance of 25.9A. It indicates that the complex is not in a catalytically active state, and structural rearrangement of RsmH or the nucleotides neighboring C1402 may be necessary to trigger catalysis. Although there is only one molecule in the asymmetric unit of the crystals, RsmH can form a compact dimer across a crystallographic twofold axis. Further analysis of RsmH by small-angle X-ray scattering (SAXS) also revealed the dimer in solution, but with a more flexible conformation than that in crystal, likely resulting from the absence of the substrate. It implies that an active status of RsmH in vivo is achieved by a formation of the dimeric architecture. In general, crystal and solution structural analysis provides new information on the mechanism of the methylation of the fine-tuning ribosomal decoding center by the RsmH.
Crystal and solution structures of methyltransferase RsmH provide basis for methylation of C1402 in 16S rRNA.,Wei Y, Zhang H, Gao ZQ, Wang WJ, Shtykova EV, Xu JH, Liu QS, Dong YH J Struct Biol. 2012 Apr 27. PMID:22561317[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Carrion M, Gomez MJ, Merchante-Schubert R, Dongarra S, Ayala JA. mraW, an essential gene at the dcw cluster of Escherichia coli codes for a cytoplasmic protein with methyltransferase activity. Biochimie. 1999 Aug-Sep;81(8-9):879-88. PMID:10572301
- ↑ Kimura S, Suzuki T. Fine-tuning of the ribosomal decoding center by conserved methyl-modifications in the Escherichia coli 16S rRNA. Nucleic Acids Res. 2010 Mar;38(4):1341-52. doi: 10.1093/nar/gkp1073. Epub 2009, Dec 3. PMID:19965768 doi:10.1093/nar/gkp1073
- ↑ Wei Y, Zhang H, Gao ZQ, Wang WJ, Shtykova EV, Xu JH, Liu QS, Dong YH. Crystal and solution structures of methyltransferase RsmH provide basis for methylation of C1402 in 16S rRNA. J Struct Biol. 2012 Apr 27. PMID:22561317 doi:10.1016/j.jsb.2012.04.011
