Your browser doesn't support javascript.
loading
SepM mutation in Streptococcus mutans clinical isolates and related function analysis.
Liu, Shanshan; Shao, Yidan; Zhang, Zhenzhen; Xu, Wen; Liu, Yudong; Zhang, Kai; Xu, Li; Zheng, Qingwei; Sun, Yu.
Affiliation
  • Liu S; Department of Stomatology, The First Affiliated Hospital of Bengbu Medical College, 287 Chuang Huai Road, Bengbu, 233004, China.
  • Shao Y; Anhui Key Laboratory of Infection and Immunity, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030, China.
  • Zhang Z; Anhui Key Laboratory of Infection and Immunity, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030, China.
  • Xu W; Department of Stomatology, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030, China.
  • Liu Y; Department of Biochemistry and Molecular Biology, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030, China.
  • Zhang K; Department of Histology and Embryology, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030, China.
  • Xu L; Department of Stomatology, The First Affiliated Hospital of Bengbu Medical College, 287 Chuang Huai Road, Bengbu, 233004, China.
  • Zheng Q; Department of Stomatology, The First Affiliated Hospital of Bengbu Medical College, 287 Chuang Huai Road, Bengbu, 233004, China.
  • Sun Y; Anhui Key Laboratory of Infection and Immunity, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030, China. bio_zqw@bbmc.edu.cn.
BMC Oral Health ; 24(1): 730, 2024 Jun 25.
Article de En | MEDLINE | ID: mdl-38918777
ABSTRACT

BACKGROUND:

Streptococcus mutans (S. mutans) is an important pathogenic bacterium that causes dental caries, while Streptococcus gordonii (S. gordonii) is a non-cariogenic bacterium that inhibits the growth of S. mutans. The SepM protein can promote the inhibitory ability of S. mutans against S. gordonii by cleaving CSP-21 and activating the ComDE two-component system. This study was designed to explore sepM mutation in S. mutans clinical isolates and related function in the regulation of interactions with S. gordonii.

METHODS:

The S. mutans clinical strains that can inhibit the growth of S. gordonii constitute the inhibitory group. 286 C-serotype S. mutans strains were categorized into S. gordonii inhibitory (n = 114) and non-inhibitory bacteria (n = 172). We detected sanger sequencing of sepM gene, the expression levels of related genes and proteins in clinical isolates, obtained prokaryotic expression and purification of mutated proteins, and analyzed the effect of the target mutations on the binding between SepM and CSP-21.

RESULTS:

We found that C482T, G533A, and G661A missense mutations were presented at significantly higher frequency in the inhibitory group relative to the non-inhibitory group. There was no significant difference in the expression of the sepM gene between selected clinical isolates harboring the G533A mutation and the control group. The expression levels of SepM, phosphorylated ComD, and ComE in the mutation group were significantly higher than those in the control group. SepM_control and SepM_D221N (G661A at the gene level) were found to contain two residues close to the active center while SepM_G178D (G533A at the gene level) contained three residues close to the active center. At 25 °C and a pH of 5.5, SepM_D221N (G661A) exhibited higher affinity for CSP-21 (KD = 8.25 µM) than did the SepM control (KD = 33.1 µM), and at 25 °C and a pH of 7.5, SepM_G178D (G533A) exhibited higher affinity (KD = 3.02 µM) than the SepM control (KD = 15.9 µM). It means that it is pH dependent.

CONCLUSIONS:

Our data suggest that increased cleavage of CSP-21 by the the mutant SepM may be a reason for the higher inhibitory effect of S. mutans on S. gordonii .
Sujet(s)
Mots clés

Texte intégral: 1 Collection: 01-internacional Base de données: MEDLINE Sujet principal: Streptococcus mutans / Protéines bactériennes / Streptococcus gordonii Limites: Humans Langue: En Journal: BMC Oral Health Sujet du journal: ODONTOLOGIA Année: 2024 Type de document: Article Pays d'affiliation: Chine

Texte intégral: 1 Collection: 01-internacional Base de données: MEDLINE Sujet principal: Streptococcus mutans / Protéines bactériennes / Streptococcus gordonii Limites: Humans Langue: En Journal: BMC Oral Health Sujet du journal: ODONTOLOGIA Année: 2024 Type de document: Article Pays d'affiliation: Chine