A comparative study of the kinetics and stereochemistry of the serine hydroxymethyltransferase- and tryptophan synthase-catalysed exchange of the pro-2<i>R</i> and pro-2<i>S</i> protons of glycine

Malthouse, J. Paul G.; Milne, J J; Gariani, Lutfi S.

doi:10.1042/bj2740807

Cited by 20 publications

(30 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4) in such a way that the C,-C, bond to be cleaved is nearly perpendicular to the pyridine ring, consistently with hypothesis (Dunathan, 1966). The model also explains the stereochemical study (Malthouse et al, 1991), which showed that the enzymes catalyze the exchange of the pro-2S proton of glycine, which is stereochemically equivalent of hydroxyl group of serine, 7,400 times faster than the pro-2R proton.…”

Section: Resultssupporting

confidence: 72%

The structure of serine hydroxymethyltransferase as modeled by homology and validated by site‐directed mutagenesis

Pascarella¹,

Angelaccio²,

Contestabile³

et al. 1998

Protein Science

View full text Add to dashboard Cite

We describe a model for the three-dimensional structure of E. coli serine hydroxymethyltransferase based on its sequence homology with other PLP enzymes of the a-family and whose tertiary structures are known. The model suggests that certain amino acid residues at the putative active site of the enzyme can adopt specific roles in the catalytic mechanism. These proposals were supported by analysis of the properties of a number of site-directed mutants. New active site features are also proposed for further experimental testing.Keywords: aspartate aminotransferase; catalysis; evolution; homology modeling; profile analysis; pyridoxal phosphate; serine hydroxymethyltransferase; site-directed mutagenesis Serine hydroxymethyltransferase (SHMT: E.C. 2.1.2. I ) catalyzes the reversible conversion of serine and tetrahydropteroyglutamate (H,PteGlu) to glycine and 5, IO-methylene-H4PteG1u (Schirch, 1982). This reaction is the major source of one-carbon groups required in the biosynthesis of methionine, choline, thymidylate, and purines. The SHMT enzyme is widely distributed in nature, and found in both prokaryotic and eukaryotic cells with the latter containing both cytosolic and mitochondrial forms. In addition to H4PteGlu, the enzyme also requires pyridoxal 5'-phosphate (PLP) as a coenzyme. It is one of a group of PLP enzymes that cleave one of the bonds at the a-carbon of their amino acid substrate. These are referred to as the a-family of PLP enzymes and include the transaminases and amino acid decarboxylases (Alexander et al.. 1 994).Three-dimensional structures have been determined for several members of the a-family of vitamin B6-dependent enzymes. Amongst them are aspartate aminotransferase (AAT; McPhalen et al., 1992;Okamoto et al., 1994;Malashkevich et al., 1995). tyrosine phenol-lyase (ITPL) (Antson et al., 1993), w-amino acid aminotransferase (Watanabe et al., 1989), 2,2-dialkylglycine decarboxylase (2DKB) (Toney et al., 1995), ornithine aminotransferase (Shen et al., 1994), glutamate-1-semialdehyde aminomutase (Henning et al., 1997), and ornithine decarboxylase (IORD) (Momany et al., 1995a). Despite the widely differing reaction speciReprint requests to: Francesco Bossa, Dipartimento di Scienze Biochimiche, Universita La Sapienza, P. le A. Moro, 5, 00185 Rorna, Italy; e-mail: BOSSA@axrma.uniromal .it. ficity and weak sequence similarity, these proteins share the same basic folding pattern, which was assumed also for SHMT (Pascarella et al., 1993). The prolonged unavailability of the SHMT atomic structure prompted the construction of a three-dimensional "homology" model that integrated knowledge regarding the enzyme acquired through site-directed mutagenesis experiments and other experimental measures. Escherichia coli SHMT was modeled because experimental data are readily available for this enzyme. New features of the active site are proposed for further experimental testing. Results and discussionHomology modeling was based on the multiple sequence alignment displayed in Figure 1.Comparison between ...

show abstract

Section: Resultssupporting

confidence: 72%

The structure of serine hydroxymethyltransferase as modeled by homology and validated by site‐directed mutagenesis

Pascarella¹,

Angelaccio²,

Contestabile³

et al. 1998

Protein Science

View full text Add to dashboard Cite

show abstract

“…The addition of the substrate (serine and glycine) leads to the formation of the external aldimine via a geminal diamine. An abstraction of a proton stereospecifically from the 2-S position of the glycineexternal aldimine complex leads to the formation of the quinonoid intermediate (39). This proton abstraction is facilitated by the presence of H 4 -folate.…”

mentioning

confidence: 99%

The Role of His-134, -147, and -150 Residues in Subunit Assembly, Cofactor Binding, and Catalysis of Sheep Liver Cytosolic Serine Hydroxymethyltransferase

Junutula

Sharma

Rao

et al. 1997

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…This result suggests that the catalytic antibody has preferentially catalysed the exchange of the pro‐2S proton of glycine. The unexchanged proton should be the pro‐2R proton of glycine which should be preferentially exchanged by tryptophan synthase [16]. After incubating the catalytic antibody with [2‐ 13 C]glycine for 32 days at 25°C there was 86% exchange of one of the α‐protons of glycine (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Fifteen μM tryptophan synthase and 1.4 μM serine hydroxymethyltransferase were incorporated into the appropriate samples. When adding serine hydroxymethyltransferase full anaerobic precautions were taken and 5 mM 2‐mercaptoethanol and 0.2 mM tetrahydrofolic acid were incorporated into the sample [16].…”

Section: Methodsmentioning

confidence: 99%

The pyridoxal‐5′‐phosphate‐dependent catalytic antibody 15A9: its efficiency and stereospecificity in catalysing the exchange of the α‐protons of glycine

et al. 1998

View full text Add to dashboard Cite

IQ C-NMR has been used to follow the exchange of the K K-protons of [2-IQ C]glycine in the presence of pyridoxal-5P-phosphate and the catalytic antibody 15A9. In the presence of antibody 15A9 the 1st order exchange rates for the rapidly exchanged proton of [2-IQ C]glycine were only 25 and 150 times slower than those observed with tryptophan synthase (EC 4.2.1.20) and serine hydroxymethyltransferase (EC 2.1.2.1). The catalytic antibody increases the 1st order exchange rates of the K K-protons of [2-IQ C]glycine by at least three orders of magnitude. We propose that this increase is largely due to an entropic mechanism which results from binding the glycinepyridoxal-5P-phosphate Schiff base. The 1st and 2nd order exchange rates of the pro-2S proton have been determined but we were only able to determine the 2nd order exchange rate for the pro-2R proton of glycine. In the presence of 50 mM glycine the antibody preferentially catalyses the exchange of the pro-2S proton of glycine. The stereospecificity of the 2nd order exchange reaction was quantified and we discuss mechanisms which could account for the observed stereospecificity.z 1998 Federation of European Biochemical Societies.

show abstract

A comparative study of the kinetics and stereochemistry of the serine hydroxymethyltransferase- and tryptophan synthase-catalysed exchange of the pro-2R and pro-2S protons of glycine

Cited by 20 publications

References 32 publications

The structure of serine hydroxymethyltransferase as modeled by homology and validated by site‐directed mutagenesis

The structure of serine hydroxymethyltransferase as modeled by homology and validated by site‐directed mutagenesis

The Role of His-134, -147, and -150 Residues in Subunit Assembly, Cofactor Binding, and Catalysis of Sheep Liver Cytosolic Serine Hydroxymethyltransferase

The pyridoxal‐5′‐phosphate‐dependent catalytic antibody 15A9: its efficiency and stereospecificity in catalysing the exchange of the α‐protons of glycine

Contact Info

Product

Resources

About