EMBO Rep 2003 Mar;4(3):296-300
Department of Biological Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
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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
Proc Natl Acad Sci U S A 2000 Aug;97(18):9925-30
Abteilung Molekulare Genetik und Präparative Molekularbiologie, Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Grisebachstrasse 8, D-37077 Göttingen, Germany.
Enzymes participating in different metabolic pathways often have similar catalytic mechanisms and structures, suggesting their evolution from a common ancestral precursor enzyme. We sought to create a precursor-like enzyme for N'-[(5'-phosphoribosyl)formimino]-5-aminoimidazole-4-carboxamide ribonucleotide (ProFAR) isomerase (HisA; EC ) and phosphoribosylanthranilate (PRA) isomerase (TrpF; EC ), which catalyze similar reactions in the biosynthesis of the amino acids histidine and tryptophan and have a similar (betaalpha)(8)-barrel structure. Using random mutagenesis and selection, we generated several HisA variants that catalyze the TrpF reaction both in vivo and in vitro, and one of these variants retained significant HisA activity. Read More
Acta Crystallogr D Biol Crystallogr 2004 Mar 25;60(Pt 3):534-6. Epub 2004 Feb 25.
Department of Biological Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, England.
The priA gene encoding the enzyme phosphoribosyl isomerase from Streptomyces coelicolor, a novel bifunctional enzyme involved in both histidine and tryptophan biosynthesis, was heterologously expressed and purified in Escherichia coli as an N-terminal His-tag fusion. The purified recombinant enzyme was crystallized using the hanging-drop method in 1.50 M ammonium sulfate and 100 mM sodium citrate pH 4. Read More
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.
Despite the prominent role of horizontal gene transfer (HGT) in shaping bacterial metabolism, little is known about the impact of HGT on the evolution of enzyme function. Specifically, what is the influence of a recently acquired gene on the function of an existing gene? For example, certain members of the genus Corynebacterium have horizontally acquired a whole l-tryptophan biosynthetic operon, whereas in certain closely related actinobacteria, for example, Mycobacterium, the trpF gene is missing. In Mycobacterium, the function of the trpF gene is performed by a dual-substrate (βα)8 phosphoribosyl isomerase (priA gene) also involved in l-histidine (hisA gene) biosynthesis. Read More