Mol Biol Evol 2013 Sep 25;30(9):2024-34. Epub 2013 Jun 25.
Evolution of Metabolic Diversity Laboratory, Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Cinvestav-IPN, Irapuato, México.
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Biochem J 2016 05 29;473(9):1141-52. Epub 2016 Feb 29.
Evolution of Metabolic Diversity Laboratory, Unidad de Genómica Avanzada (Langebio), Cinvestav-IPN, Irapuato, CP36821, México
We investigate the evolution of co-occurring analogous enzymes involved in L-tryptophan and L-histidine biosynthesis in Actinobacteria Phylogenetic analysis of trpF homologues, a missing gene in certain clades of this lineage whose absence is complemented by a dual-substrate HisA homologue, termed PriA, found that they fall into three categories: (i) trpF-1, an L-tryptophan biosynthetic gene horizontally acquired by certain Corynebacterium species; (ii) trpF-2, a paralogue known to be involved in synthesizing a pyrrolopyrrole moiety and (iii) trpF-3, a variable non-conserved orthologue of trpF-1 We previously investigated the effect of trpF-1 upon the evolution of PriA substrate specificity, but nothing is known about the relationship between trpF-3 and priA After in vitro steady-state enzyme kinetics we found that trpF-3 encodes a phosphoribosyl anthranilate isomerase. However, mutation of this gene in Streptomyces sviceus did not lead to auxothrophy, as expected from the biosynthetic role of trpF-1 Biochemical characterization of a dozen co-occurring TrpF-2 or TrpF-3, with PriA homologues, explained the prototrophic phenotype, and unveiled an enzyme activity trade-off between TrpF and PriA. X-ray structural analysis suggests that the function of these PriA homologues is mediated by non-conserved mutations in the flexible L5 loop, which may be responsible for different substrate affinities. Read More
Proc Natl Acad Sci U S A 2011 Mar 14;108(9):3554-9. Epub 2011 Feb 14.
European Molecular Biology Laboratory, Hamburg Unit, Notkestrasse 85, D-22603 Hamburg, Germany.
In histidine and tryptophan biosynthesis, two related isomerization reactions are generally catalyzed by two specific single-substrate enzymes (HisA and TrpF), sharing a similar (β/α)(8)-barrel scaffold. However, in some actinobacteria, one of the two encoding genes (trpF) is missing and the two reactions are instead catalyzed by one bisubstrate enzyme (PriA). To unravel the unknown mechanism of bisubstrate specificity, we used the Mycobacterium tuberculosis PriA enzyme as a model. Read More
EMBO Rep 2003 Mar;4(3):296-300
Department of Biological Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
We report the occurrence of an isomerase with a putative (betaalpha)(8)-barrel structure involved in both histidine and trypto-phan biosynthesis in Streptomyces coelicolor A3(2) and Mycobacterium tuberculosis HR37Rv. Deletion of a hisA homologue (SCO2050) putatively encoding N'-[(5'-phosphoribosyl)-formimino]-5 amino-imidazole-4-carboxamide ribonucleotide isomerase from the chromosome of S. coelicolor A3(2) generated a double auxotrophic mutant for histidine and tryptophan. Read More
Biochemistry 2002 Oct;41(40):12032-42
Institut für Biochemie, Universität zu Köln, Otto-Fischer-Strasse 12-14, D-50674 Köln, Germany.
The enzymes N'-[(5'-phosphoribosyl)formimino]-5-aminoimidazole-4-carboxamide ribonucleotide isomerase (HisA) and phosphoribosylanthranilate isomerase (TrpF) are sugar isomerases that are involved in histidine and tryptophan biosynthesis, respectively. Both enzymes have the (betaalpha)(8)-barrel fold and catalyze Amadori rearrangements of a thermolabile aminoaldose into the corresponding aminoketose. To identify those amino acids that are essential for catalysis, conserved residues at the active sites of both HisA and TrpF from the hyperthermophile Thermotoga maritima were replaced by site-directed mutagenesis, and the purified variants were investigated by steady-state enzyme kinetics. Read More