Structure of Escherichia coli K-12 miaA and characterization of the mutator phenotype caused by miaA insertion mutations - PubMed (original) (raw)

Structure of Escherichia coli K-12 miaA and characterization of the mutator phenotype caused by miaA insertion mutations

D M Connolly et al. J Bacteriol. 1991 Mar.

Abstract

Previously, we reported several unusual relationships between the 2-methylthio-N6-(delta 2-isopentenyl)adenosine-37 (ms2i6A-37) tRNA modification and spontaneous mutagenesis in Escherichia coli K-12 (D. M. Connolly and M. E. Winkler, J. Bacteriol. 171:3233-3246, 1989). To confirm and extend these observations, we determined the structure of miaA, which mediates the first step of ms2i6A-37 synthesis, and characterized the miaA mutator phenotype. The most likely translation start of miaA overlaps the last two codons of mutL, which encodes a protein required for methyl-directed mismatch repair. This structural arrangement confirms that miaA and mutL are in the same complex operon. The miaA gene product, delta 2-isopentenylpyrophosphate transferase, shows extensive homology with the yeast MOD5 gene product, and both enzymes contain a substrate binding site found in farnysyl pyrophosphate synthetase and a conserved putative ATP/GTP binding site. Insertions in miaA cause exclusively GC----TA transversions, which contrasts with the GC----AT and AT----GC transitions observed in mutL mutants. To correlate the absence of the ms2i6A-37 tRNA modification directly with the mutator phenotype, we isolated a unique suppressor of a leaky miaA(ochre) mutation. The miaD suppressor mapped to 99.75 min, restored the ms2i6A-37 tRNA modification to miaA(ochre) mutants, and abolished the miaA mutator phenotype. We speculate that miaD causes a decrease in ms2i6A-37 tRNA demodification or an increase in miaA gene expression but not at the level of operon transcription. Together, these observations support the idea that the ms2i6A-37 tRNA modification acts as a physiological switch that modulates spontaneous mutation frequency and other metabolic functions.

PubMed Disclaimer

Cited by

A tRNA modifying enzyme as a tunable regulatory nexus for bacterial stress responses and virulence.
Fleming BA, Blango MG, Rousek AA, Kincannon WM, Tran A, Lewis AJ, Russell CW, Zhou Q, Baird LM, Barber AE, Brannon JR, Beebout CJ, Bandarian V, Hadjifrangiskou M, Howard MT, Mulvey MA. Fleming BA, et al. Nucleic Acids Res. 2022 Jul 22;50(13):7570-7590. doi: 10.1093/nar/gkac116. Nucleic Acids Res. 2022. PMID: 35212379 Free PMC article.
Biogenesis and functions of aminocarboxypropyluridine in tRNA.
Takakura M, Ishiguro K, Akichika S, Miyauchi K, Suzuki T. Takakura M, et al. Nat Commun. 2019 Dec 5;10(1):5542. doi: 10.1038/s41467-019-13525-3. Nat Commun. 2019. PMID: 31804502 Free PMC article.
The Odyssey of the Ancestral Escherich Strain through Culture Collections: an Example of Allopatric Diversification.
Desroches M, Royer G, Roche D, Mercier-Darty M, Vallenet D, Médigue C, Bastard K, Rodriguez C, Clermont O, Denamur E, Decousser JW. Desroches M, et al. mSphere. 2018 Jan 31;3(1):e00553-17. doi: 10.1128/mSphere.00553-17. eCollection 2018 Jan-Feb. mSphere. 2018. PMID: 29404421 Free PMC article.
Cytokinin Metabolism of Pathogenic Fungus Leptosphaeria maculans Involves Isopentenyltransferase, Adenosine Kinase and Cytokinin Oxidase/Dehydrogenase.
Trdá L, Barešová M, Šašek V, Nováková M, Zahajská L, Dobrev PI, Motyka V, Burketová L. Trdá L, et al. Front Microbiol. 2017 Jul 21;8:1374. doi: 10.3389/fmicb.2017.01374. eCollection 2017. Front Microbiol. 2017. PMID: 28785249 Free PMC article.
TrmL and TusA Are Necessary for rpoS and MiaA Is Required for hfq Expression in Escherichia coli.
Aubee JI, Olu M, Thompson KM. Aubee JI, et al. Biomolecules. 2017 May 4;7(2):39. doi: 10.3390/biom7020039. Biomolecules. 2017. PMID: 28471404 Free PMC article.

References

1. J Biol Chem. 1979 Aug 10;254(15):7362-7 - PubMed
1. Nucleic Acids Res. 1990 Jul 11;18(13):3841-5 - PubMed
1. Biochem Biophys Res Commun. 1970 Sep 30;40(6):1481-7 - PubMed
1. Nucleic Acids Res. 1975 May;2(5):691-8 - PubMed
1. Biochem Biophys Res Commun. 1975 Jul 8;65(1):345-51 - PubMed

Structure of Escherichia coli K-12 miaA and characterization of the mutator phenotype caused by miaA insertion mutations - PubMed (original) (raw)