J. Biol. Chem., Vol. 260, Issue 5, 2798-2803, Mar, 1985
Pyruvoyl-dependent histidine decarboxylases. Preparation and amino acid sequences of the beta chains of histidine decarboxylase from Clostridium perfringens and Lactobacillus buchneri
QK Huynh and EE Snell
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.