Structural insights into catalysis by beta C-S lyase from Streptococcus anginosusKezuka, Y., Yoshida, Y., Nonaka, T.
(2012) Proteins 80: 2447-2458
- PubMed: 22674431
- DOI: 10.1002/prot.24129
- Primary Citation of Related Structures:
3B1C, 3B1D, 3B1E
- PubMed Abstract:
- Crystallization and preliminary X-ray analysis of betaC-S lyases from two oral Streptococci
Kezuka, Y., Yoshida, Y., Nonaka, T.
(2009) Acta Crystallogr Sect F Struct Biol Cryst Commun 65: 874
- Molecular and enzymatic characterization of betaC-S lyase in Streptococcus constellatus
Yoshida, Y., Ito, S., Sasaki, T., Kishi, M., Kurota, M., Suwabe, A., Kunimatsu, K., Kato, H.
(2008) Oral Microbiol Immunol 23: 245
- Differences in the betaC-S lyase activities of viridans group streptococci
Yoshida, Y., Negishi, M., Amano, A., Oho, T., Nakano, Y.
(2003) Biochem Biophys Res Commun 300: 55
- lcd from Streptococcus anginosus encodes a C-S lyase with alpha,beta-elimination activity that degrades L-cysteine
Yoshida, Y., Nakano, Y., Amano, A., Yoshimura, M., Fukamachi, H., Oho, T., Koga, T.
(2002) Microbiology (N Y) 148: 3961
Hydrogen sulfide (H(2)S) is a causative agent of oral malodor and may play an important role in the pathogenicity of oral bacteria such as Streptococcus anginosus. In this microorganism, H(2)S production is associated with βC-S lyase (Lcd) encoded by lcd gene, which is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the α,β-elimination of sulfur-containing amino acids ...
Hydrogen sulfide (H(2)S) is a causative agent of oral malodor and may play an important role in the pathogenicity of oral bacteria such as Streptococcus anginosus. In this microorganism, H(2)S production is associated with βC-S lyase (Lcd) encoded by lcd gene, which is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the α,β-elimination of sulfur-containing amino acids. When Lcd acts on L-cysteine, H(2)S is produced along with pyruvate and ammonia. To understand the H(2)S-producing mechanism of Lcd in detail, we determined the crystal structures of substrate-free Lcd (internal aldimine form) and two reaction intermediate complexes (external aldimine and α-aminoacrylate forms). The formation of intermediates induced little changes in the overall structure of the enzyme and in the active site residues, with the exception of Lys234, a PLP-binding residue. Structural and mutational analyses highlighted the importance of the active site residues Tyr60, Tyr119, and Arg365. In particular, Tyr119 forms a hydrogen bond with the side chain oxygen atom of L-serine, a substrate analog, in the external aldimine form suggesting its role in the recognition of the sulfur atom of the true substrate (L-cysteine). Tyr119 also plays a role in fixing the PLP cofactor at the proper position during catalysis through binding with its side chain. Finally, we partly modified the catalytic mechanism known for cystalysin, a βC-S lyase from Treponema denticola, and proposed an improved mechanism, which seems to be common to the βC-S lyases from oral bacteria.
Department of Structural Biology, School of Pharmacy, Iwate Medical University, Yahaba, Iwate, Japan.