Structural Comparison of <i>Streptococcus mutans</i> Dextran Glucosidase with Glucoside Hydrolases in GH13

Hironori Hondoh; Hiroaki Otsuka-Rachi; Wataru Saburi; Haruhide Mori; Masayuki Okuyama; Atsuo Kimura

doi:10.5458/jag.56.111

Structural Comparison of Streptococcus mutans Dextran Glucosidase with Glucoside Hydrolases in GH13

Journal of Applied Glycoscience ◽

10.5458/jag.56.111 ◽

2009 ◽

Vol 56 (2) ◽

pp. 111-117 ◽

Cited By ~ 1

Author(s):

Hironori Hondoh ◽

Hiroaki Otsuka-Rachi ◽

Wataru Saburi ◽

Haruhide Mori ◽

Masayuki Okuyama ◽

...

Keyword(s):

Streptococcus Mutans ◽

Structural Comparison ◽

Glucoside Hydrolases

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Mechanism of the allosteric regulation ofStreptococcus mutans2′-deoxycytidylate deaminase

Acta Crystallographica Section D Structural Biology ◽

10.1107/s2059798316009153 ◽

2016 ◽

Vol 72 (7) ◽

pp. 883-891 ◽

Cited By ~ 3

Author(s):

Yanhua Li ◽

Zhen Guo ◽

Li Jin ◽

Deqiang Wang ◽

Zengqiang Gao ◽

...

Keyword(s):

Crystal Structure ◽

Protein Binding ◽

Streptococcus Mutans ◽

Specific Activity ◽

Allosteric Regulation ◽

Calorimetric Data ◽

Structural Comparison ◽

Inactive Conformation ◽

Gram Positive Bacteria ◽

Allosteric Mechanism

In cells, dUMP is the intermediate precursor of dTTP in its synthesis during deoxynucleotide metabolism. In Gram-positive bacteria and eukaryotes, zinc-dependent deoxycytidylate deaminases (dCDs) catalyze the conversion of dCMP to dUMP. The activity of dCD is allosterically activated by dCTP and inhibited by dTTP. Here, the crystal structure ofStreptococcus mutansdCD (SmdCD) complexed with dTTP is presented at 2.35 Å resolution, thereby solving the first pair of activator-bound and inhibitor-bound structures from the same species to provide a more definitive description of the allosteric mechanism. In contrast to the dTTP-bound dCD from the bacteriophage S-TIM5 (S-TIM5-dCD), dTTP-bound SmdCD adopts an inactive conformation similar to the apo form. A structural comparison suggests that the distinct orientations of the triphosphate group in S-TIM5-dCD and SmdCD are a result of the varying protein binding environment. In addition, calorimetric data establish that the modulators bound to dCD can be mutually competitively replaced. The results reveal the mechanism underlying its regulator-specific activity and might greatly enhance the understanding of the allosteric regulation of other dCDs.

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Cell Wall Ultrastructure in Three Strains of a Cariogenic Streptococcus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065730 ◽

1971 ◽

Vol 29 ◽

pp. 338-339

Author(s):

M. J. Kramer ◽

Alan L. Coykendall

Keyword(s):

Cell Wall ◽

Dental Caries ◽

Streptococcus Mutans ◽

Microscopic Study ◽

Electron Microscopic Study ◽

Genetic Heterogeneity ◽

Morphological Characteristics ◽

Electron Microscopic ◽

Dna Reassociation ◽

Wall Ultrastructure

During the almost 50 years since Streptococcus mutans was first suggested as a factor in the etiology of dental caries, a multitude of studies have confirmed the cariogenic potential of this organism. Streptococci have been isolated from human and animal caries on numerous occasions and, with few exceptions, they are not typable by the Lancefield technique but are relatively homogeneous in their biochemical reactions. An analysis of the guanine-cytosine (G-C) composition of the DNA from strains K-1-R, NCTC 10449, and FA-1 by one of us (ALC) revealed significant differences and DNA-DNA reassociation experiments indicated that genetic heterogeneity existed among the three strains. The present electron microscopic study had as its objective the elucidation of any distinguishing morphological characteristics which might further characterize the respective strains.

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The role of intracanal medicaments in inhibition of bacteria isolated from root canals of infected primary molars

Mustansiria Dental Journal ◽

10.32828/mdj.v14i1.766 ◽

2019 ◽

Vol 14 (1) ◽

pp. 92

Author(s):

Dr. Maha Abdul- Kareem Mahmood ◽

Dr. Huda Elias Ali ◽

Dr. Haraa Khairi Abdul-Kadher

Keyword(s):

Antimicrobial Activity ◽

Streptococcus Mutans ◽

Normal Saline ◽

Root Canal ◽

Primary Teeth ◽

Primary Molars ◽

Root Canals ◽

Etiologic Agents ◽

Micro Organisms

Microbes are considered as the primary etiologic agents in endodontic diseases.Disinfection of the root canal is obtained by the combined effect of biomechanicalpreparation, irrigation and intra canal medicament. The aim of the present study wasto assess the antimicrobial activity of intracanal medicaments (formocresol andEndosepton) against two micro organisms (Streptococcus mutans and staphylococcusaureus) isolated from 15 necrotic pulps of primary molars indicated for pulpectomyprocedure. The samples were cultured, and purified using microbiological evaluation.Broth dilution test was performed in our study by preparing test tubes containing10 ml of BHI broth (pH. 7) which then inoculated with strains of the tested bacteriaand incubated at 37 C° for 24 h. After over night incubaction, ten fold dilution weremade in test tubes containing 9 ml of normal saline by adding 1 ml of the inoculum tothe first tube . Then from dilution 10-1 , 0.1 ml of cell suspension was added to 9.9 mlof formocresol and endosepton, then 0.1 ml was taken and spread on duplicates ofBHI agar plates at different intervals and incubated aerobically for 24 h. at 37 C°.Colonies on the plates were counted after incubation and CFU/mL (colony formingunit) was calculated. Our results indicating that there were no significant differencesbetween the intracanal medicaments, but there were high significant differencesbetween the intervals time of the study. We concluded that both materials had greatantibacterial effect against the pathogens commonly isolated from necrotic pulpaltissue of primary teeth.

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