Cloning and nucleotide sequences of the genes encoding triose phosphate isomerase, phosphoglycerate mutase, and enolase from Bacillus subtilis

Abstract

The Bacilus subtilis genes tpi, pgm, and eno, encoding triose phosphate isomerase, phosphoglycerate mutase (PGM), and enolase, respectively, have been cloned and sequenced. These genes are the last three in a large putative operon coding for glycolytic enzymes; the operon includes pgk (coding for phosphoglycerate kinase) followed by tpi, pgm, and eno. The triose phosphate isomerase and enolase from B. subtilis are extremely similar to those from all other species, both eukaryotic and prokaryotic. However, B. subtilis PGM bears no resemblance to mammalian, fungal, or gram-negative bacterial PGMs, which are dependent on 2,3-diphosphoglycerate (DPG) for activity. Instead, B. subtilis PGM, which is DPG independent, is very similar to a DPG-independent PGM from a plant species but differs from the latter in the absolute requirement of B. subtilis PGM for Mn2 . The cloned pgm gene has been used to direct up to 25-fold overexpression of PGM in Escherichia coli; this should facilitate purification of large amounts of this novel Mn2'-dependent enzyme.Inactivation ofpgm plus eno in B. subtilis resuIted in extremely slow growth either on plates or in liquid, but growth of these mutants was enhanced by supplementation of media with malate. However, these mutants were asporogenous with or without malate supplementation.The process of sporulation in Bacillus and Clostridium species produces a spore which is extremely resistant to a variety of harsh treatments, such as heat, dessication and radiation, and which can survive for long periods in the absence of exogenous nutrients (19). One reason for the survival of spores in such conditions is that they are metabolically dormant and carry out neither macromolecular biosynthesis nor detectable metabolism of exogenous or endogenous compounds (17-19). Not surprisingly, dormant spores lack significant levels of products of catabolism such as ATP and NADH, which are present at high levels in growing cells, although AMP and NAD are present at significant levels in spores (18). While the spore can remain in this dormant state for long periods of time, with the proper stimulus spore germination is initiated, and within minutes ATP and NADH are produced and macromolecular biosynthesis begins (17, 18). The dormant spore contains a number of energy reserves which are mobilized in the first minutes of germination, thus facilitating the rapid resumption of metabolism. One such reserve is the large depot of small, acid-soluble proteins which are degraded to amino acids early in germination, with a significant amount of these amino acids catabolized for energy (17,18). A second energy reserve is a depot of 3-phosphoglyceric acid (3PGA), which constitutes 0.2 to 0.5% of spore dry weight (18). The 3PGA depot is accumulated late in sporulation within the developing spore, and there is a body of evidence indicating that phosphoglycerate mutase (PGM) is the enzyme which is specifically inhibited to allow 3PGA accumulation (18,20,22). In the first minutes of germination, the 3PGA depot is converted ...

Analysis of the Function of a Putative 2,3-Diphosphoglyceric Acid-Dependent Phosphoglycerate Mutase from Bacillus subtilis

“…In addition, deletion of the gene coding for this enzyme had a huge effect on cell growth (13). These data strongly suggest that, under the conditions that have been tested, B. subtilis has and needs only one PGM, an iPGM.…”

“…In Bacillus subtilis the great majority (Ն90%) of PGM activity is due to an iPGM (20,26), and mutation of the coding gene (termed pgm) has very severe effects on cell growth, especially in the presence of glucose (13). Although this iPGM appears to be the major PGM in B. subtilis, determination of the complete sequence of the B. subtilis genome revealed only a single gene, termed yhfR, that codes for a protein with significant sequence similarity to dPGMs (11), (see below).…”

A null mutation in the Bacillus subtilis aconitase gene causes a block in Spo0A-phosphate-dependent gene expression

“…A candidate target is phosphoglycerate phosphomutase, which catalyzes the interconversion of 3-phosphoglyceric acid (3-PGA) and 2-PGA in the glycolytic pathway and has a specific manganese requirement. In the absence of manganese, wild-type cells of B. subtilis stop growing at a lower than normal cell density, 3-PGA accumulates inside the cell, and sporulation is arrested before asymmetric septation (32,37). No direct relationship between accumulation of 3-PGA and the activity of the Spo0A phosphorelay has been demonstrated, however.…”

Evolution of the coordinate regulation of glycolytic enzyme genes by hypoxia

“…Evidence for glycolytic enzyme gene operons include linked pyruvate kinase and PFK genes in Clostridium acetobutylicum (Belouski et al, 1998); clustered genes for phosphoglycerate kinase (PGK), triosephosphate isomerase (TPI), phosphoglycerate mutase and enolase in Baccilus subtilis (Leyva-Vazquez and Setlow, 1994); linkage of GAPDH, PGK and TPI in Borrelia megaterium, Borrelia bungorferi and Borrelia hermsii (Gebbia et al, 1997;Schlapfer and Zuber, 1992); clustering of fructose 1,6-biphosphate aldolase, 3-phosphoglycerate kinase and GAPDH in E. coli (Alefounder and Perham 1989), and clustering of the glucose-6 dehydrogenase, 6-phosphogluconate dehydratase and glucokinase genes with a putative glucose transporter in Zymomonas mobilis (Barnell et al, 1990). These glycolytic enzyme gene operons may be regulated independently of each other or globally.…”