Molecular and enzymatic characterization of betaC-S lyase in Streptococcus constellatus.
OBJECTIVE
Streptococcus anginosus and Streptococcus constellatus are frequently isolated from dental abscesses and other suppurative lesions. We previously reported that betaC-S lyase from a strain of S. anginosus produced significantly more hydrogen sulfide than betaC-S lyases from other streptococci. The purpose of this study was to establish the molecular and enzymatic features of the betaC-S lyase in S. constellatus and to elucidate whether this unique capacity is common to many strains of S. constellatus and S. anginosus.


METHODS
The capacity of crude extract to produce hydrogen sulfide was evaluated among 16 strains of S. constellatus, S. anginosus, and Streptococcus gordonii. The lcd gene encoding betaC-S lyase was cloned from the genomic DNA of each strain to compare the deduced amino acid sequences. The recombinant betaC-S lyases of three representative strains were purified and characterized.


RESULTS
Incubation of crude extracts from all strains of S. constellatus and S. anginosus with l-cysteine resulted in the production of a large amount of hydrogen sulfide. The primary sequence of betaC-S lyase was very similar among strains of S. constellatus and S. anginosus. The kinetic properties of the betaC-S lyases purified from S. constellatus resembled those for betaC-S lyases purified from S. anginosus. In contrast, the betaC-S lyases of S. constellatus and S. gordonii differed in terms of their hydrogen sulfide production, with the former producing much more.


CONCLUSIONS
A high level of hydrogen sulfide production, which appears to be a common feature in both S. constellatus and S. anginosus, may be associated with their abscess formation.
Yoshida
Y
Y
Department of Dental Pharmacology, Iwate Medical University, Morioka, Japan. yasuoy@iwate-med.ac.jp
Ito
S
S
Sasaki
T
T
Kishi
M
M
Kurota
M
M
Suwabe
A
A
Kunimatsu
K
K
Kato
H
H
D013437:Carbon-Sulfur Lyases / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000235:genetics; D004396:Coloring Agents; D016384:Consensus Sequence / Q000235:genetics; D003540:Cystathionine / Q000032:analysis; D003545:Cysteine / Q000378:metabolism; D004269:DNA, Bacterial / Q000032:analysis; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016680:Genome, Bacterial / Q000235:genetics; D006801:Humans; D006862:Hydrogen Sulfide / Q000032:analysis; D008751:Methylene Blue; D008967:Molecular Biology; D011773:Pyruvates / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D034366:Streptococcus anginosus / Q000201:enzymology; D034365:Streptococcus constellatus / Q000201:enzymology*; D054773:Streptococcus gordonii / Q000201:enzymology
D004396:Coloring Agents; D004269:DNA, Bacterial; D004791:Enzyme Inhibitors; D011773:Pyruvates; D012336:RNA, Ribosomal, 16S; D003540:Cystathionine; D013437:Carbon-Sulfur Lyases; D003545:Cysteine; D008751:Methylene Blue; D006862:Hydrogen Sulfide