Pyruvoyl-dependent Histidine Decarboxylase Research Articles

Pyruvoyl-dependent histidine decarboxylases. Preparation and amino acid sequences of the beta chains of histidine decarboxylase from Clostridium perfringens and Lactobacillus buchneri.

Histidine decarboxylase (HisDCase) from Lactobacillus buchneri was purified to homogeneity. Its subunit structure, (alpha beta)6, and enzymatic properties resemble closely those of the immunologically cross-reactive HisDCase of Lactobacillus 30a (Recsei, P. A., and Snell, E. E. (1984) Annu. Rev. Biochem. 53, 357-387). The complete amino acid sequences of the beta chains of the HisDCase from L. buchneri (81 residues) and Clostridium perfringens (86 residues) were then determined to be a and b, respectively. (a) SEFDKKLNTLGVDRISVSPYKKWSRGYMEPGNIGNGYVSGLKVDAG VVDKTDDMVLDGIGSYDRAETKNAYIGQINMTTAS. (b) TLSEGIHKNIKNIKVRAP KIDKTAISPYDRYCDGYGMPGAYGDGYVSVLKVSVGTVKK TDDILLDGIVSYDRAEINDAYVGQINMLTAS. SEFDKKLNTLGVDRISVSPYKKWSRGYMEPGNIGNGYVSGLKVDAGVV. Although these sequences differ substantially near the NH2-terminal ends, there is striking homology near the COOH termini and also near the NH2 terminus of the two alpha chains (pyruvoyl-Phe-X-Gly-Val-, where X is Ser or Cys). If the four known pyruvoyl-dependent HisDCases arise from inactive proenzymes by the mechanism previously demonstrated for the HisDCase of Lactobacillus 30a (Recsei, P. A., Huynh, Q. K. and Snell, E. E. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 973-977), then each of these proenzymes has the sequence -Thr-Ala-Ser-Ser-Phe- at the activation site (where -Ser- becomes the COOH terminus of the beta chain and -Ser- becomes the pyruvoyl group blocking the NH2 terminus of the alpha chain), and the sequences around this activation site are highly conserved in all four enzymes. These facts support the assumptions that the four enzymes have evolved from a common ancestral protein, are formed from inactive pyruvate-free proenzymes by similar mechanisms, and have similar catalytic mechanisms.

Pyruvoyl-dependent histidine decarboxylases. Comparative sequences of cysteinyl peptides of the enzymes from Lactobacillus 30a, Lactobacillus buchneri, and Clostridium perfringens.

The two cysteinyl residues present in histidine decarboxylase from Lactobacillus 30a differ greatly in reactivity. One (class 1) reacts readily in the native state with dithiobis-(2-nitrobenzoate) with complete loss of enzyme activity; the other (class 2) reacts only after denaturation of the enzyme (Lane, R. S., and Snell, E. E. (1976) Biochemistry 15, 4175-4179). These differences in reactivity permitted use of covalent (disulfide) chromatography to isolate separate peptides that contain these two residues. Sequence analysis showed that the class 1 cysteinyl residue is at position 147 in a hydrophilic portion of the alpha chain (Huynh, Q. K., Recsei, P. A., Vaaler, G. L., and Snell, E. E. (1984) J. Biol. Chem. 259, 2833-2839), while the class 2 cysteinyl residue is present at position 71, adjacent to a hydrophobic portion of the same chain. Cysteinyl peptides identical with or homologous to the class 2 cysteinyl peptide of the Lactobacillus 30a enzyme were isolated from the alpha subunits of histidine decarboxylases from Lactobacillus buchneri and Clostridium perfringens, respectively. The L. buchneri enzyme also contained a peptide homologous to the class 1 cysteinyl peptide from Lactobacillus 30a. However, no corresponding peptide was present in the enzyme from C. perfringens, in which the second cysteinyl residue of the alpha chain occupies position 3, very near the essential pyruvoyl residue. This enzyme, unlike those from Lactobacillus 30a or L. buchneri, also contains one cysteinyl residue in its beta chain. Although Cys 147 is an active site residue in histidine decarboxylase from Lactobacillus 30a, the absence of a corresponding residue in the C. perfringens enzyme confirms previous indications (Recsei, P. A., and Snell, E. E. (1982) J. Biol. Chem. 257, 7196-7202) that this SH group is not essential for decarboxylase action.

Pyruvoyl-dependent histidine decarboxylases from Clostridium perfringens and Lactobacillus buchneri. Comparative structures and properties.

Histidine decarboxylase (EC 4.1.1.22) was purified to homogeneity from Clostridium perfringens and also from Lactobacillus buchneri. Both enzymes are composed of alpha and beta subunits, with an essential pyruvoyl group bound to the alpha subunit. In this respect and also in molecular weight of both the alpha and beta subunits and the native enzyme, they closely resemble the previously described (Riley, W.D., and Snell, E. E. (1970) Biochemistry 9, 1485-1491) histidine decarboxylase from Lactobacillus 30a. Rabbit antibodies to the latter enzyme cross-react incompletely with the decarboxylase from L. buchneri but not with that from C. perfringens in double diffusion tests. The clostridial decarboxylase differs substantially from the Lactobacillus 30a enzyme in amino acid composition and, unlike the latter enzyme, requires high ionic strength (I approximately 1.4 M) for maximum activity. The enzymes also differ in rates of electrophoretic migration. A proenzyme for the decarboxylase similar to that previously found in Lactobacillus 30a was detected in immunoprecipitates of extracts of L. buchneri. We conclude that these proteins arise from pyruvate-free precursor proteins by similar mechanisms and probably have diverged from a common ancestral protein.