Structural relationship between the enzymatic and streptococcal binding sites of human salivary α-amylase

Scannapicco, F.A.; Bhandary, K. K.; Ramasubbu, Narayanan; Levine, Michael

doi:10.1016/s0006-291x(05)80900-3

Cited by 61 publications

(67 citation statements)

References 24 publications

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“…Streptococcal binding. Previously, we have shown that the histidine residues of salivary amylase play a role in its binding to oral streptococci (Scannapieco et al, 1990). In these studies, histidine was modified with diethyl pyrocarbonate (DEP).…”

Section: Comparison Of Human Salivary and Pancreatic Amylasesmentioning

confidence: 99%

“…The location of His52 and His305 suggests that these may play a role in the substrate-binding activity. Scannapieco et al (1990) studied the extent of loss of bacterial binding activity and the enzymatic activity by modifying His residues in the presence and absence of maltotriose. The modification of His residues in the presence of excess maltotriose led to a greater loss of streptococcal binding activity than of catalytic activity (Scannapieco et al, 1990).…”

Section: Comparison Of Human Salivary and Pancreatic Amylasesmentioning

confidence: 99%

“…Scannapieco et al (1990) studied the extent of loss of bacterial binding activity and the enzymatic activity by modifying His residues in the presence and absence of maltotriose. The modification of His residues in the presence of excess maltotriose led to a greater loss of streptococcal binding activity than of catalytic activity (Scannapieco et al, 1990). This result can be considered in terms of one binding site which is used by both the substrate and bacterial adhesins or two different sites, distinct from each other, one of which is used for binding bacterial adhesins and the other for binding substrates.…”

Section: Comparison Of Human Salivary and Pancreatic Amylasesmentioning

confidence: 99%

“…Second, amylase in solution binds with high affinity to viridans oral streptococci, a function that may lead to the clearance and/or adherence of these bacteria in the oral cavity. Interestingly, amylase bound to the bacterial surface retains approximately 50% of its enzymatic activity (Scannapieco, Bergey, Reddy & Levine, 1989;Scannapieco, Bhandary, Ramasubbu & Levine, 1990;Douglas, 1990;Douglas, Heath & Gwynn, 1992). Thus, bacteria-bound amylase is capable of hydrolyzing starch to glucose, which can be used as a food source and then metabolized to lactic acid.…”

Section: Introductionmentioning

confidence: 99%

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Structure of Human Salivary α-Amylase at 1.6 Å Resolution: Implications for its Role in the Oral Cavity

Ramasubbu

Venugopalan

Luo

et al. 1996

Acta Crystallogr D Biol Crystallogr

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242

205

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Salivary a-amylase, a major component of human saliva, plays a role in the initial digestion of starch and may be involved in the colonization of bacteria involved in early dental plaque formation. The three-dimensional atomic structure of salivary amylase has been determined to understand the structure-function relationships of this enzyme. This structure was refined to an R value of 18.4% with 496 amino-acid residues, one calcium ion, one chloride ion and 170 water molecules. Salivary amylase folds into a multidomain structure consisting of three domains, A, B and C. Domain A has a (/3/a)8-barrel structure, domain B has no definite topology and domain C has a Greek-key barrel structure. The Ca 2+ ion is bound to Asnl00, Arg158, Asp167, His201 and three water molecules. The C1-ion is bound to Arg195, Asn298 and Arg337 and one water molecule. The highly mobile glycine-rich loop 304-310 may act as a gateway for substrate binding and be involved in a 'trap-release' mechanism in the hydrolysis of substrates. Strategic placement of calcium and chloride ions, as well as histidine and tryptophan residues may play a role in differentiating between the glycone and aglycone ends of the polysaccharide substrates. Salivary amylase also possesses a suitable site for binding to enamel surfaces and provides potential sites for the binding of bacterial adhesins.

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Section: Comparison Of Human Salivary and Pancreatic Amylasesmentioning

confidence: 99%

Section: Comparison Of Human Salivary and Pancreatic Amylasesmentioning

confidence: 99%

Section: Comparison Of Human Salivary and Pancreatic Amylasesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Structure of Human Salivary α-Amylase at 1.6 Å Resolution: Implications for its Role in the Oral Cavity

Ramasubbu

Venugopalan

Luo

et al. 1996

Acta Crystallogr D Biol Crystallogr

Self Cite

242

205

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“…While significant progress has been made in studies regarding bacterial proteins that bind to HSAmy, very little is known about the molecular determinants of HSAmy that are essential for the interaction. Interestingly, biochemical studies have shown the existence of a similarity between substrate and bacterial binding sites (Scannapieco et al 1990). Earlier crystallographic studies have shown that HSAmy possesses four secondary saccharide-binding sites (Fig.…”

mentioning

confidence: 99%

Structure-function relationships in human salivary α-amylase: role of aromatic residues in a secondary binding site

2008

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Human salivary α-amylase (HSAmy) has three distinct functions relevant to oral health: (i) hydrolysis of starch; (ii) binding to hydroxyapatite; and (iii) binding to bacteria (e.g. viridans streptococci). Oral bacteria utilize the starch hydrolyzing activity of HSAmy to derive their nutrients from dietary starch. Localized acid production by bacteria, through the metabolism of maltose generated by HSAmy, can lead to the dissolution of tooth enamel, a critical step in dental caries formation. HSAmy is a component of the acquired enamel pellicle and is used by Streptococcus gordonii to colonize the oral cavity. Although the active site of HSAmy for starch hydrolysis is well characterized, the regions responsible for the bacterial binding are yet to be defined. Since HSAmy possesses several secondary saccharide-binding sites in which aromatic residues are prominently located, we hypothesized that one of the secondary saccharide-binding sites harboring the aromatic residues W316 and W388, may play an important role in bacterial binding. To test this hypothesis, the aromatic residues W316 and W388 were mutated to alanine. The wild type and the mutant enzymes were characterized for their abilities to exhibit enzyme activity, starch binding and bacterial binding. Our results clearly showed that (i) the mutants W316A and W388A were not impaired in starch binding or bacterial binding; (ii) mutation of aromatic residues at theses sites does not alter the overall conformation of the molecule; and (iii) the hydrolytic activity of the enzyme is unaffected against starch as substrates but reduced significantly against oligosaccharides.

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Sialadenitis with crystalloid formation: A report of six cases diagnosed by fine‐needle aspiration

Johnson¹,

Oertel²,

Ammann³

1995

Diagnostic Cytopathology

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Six cases of sialadenitis diagnosed by fine-needle aspiration contained large numbers of crystalloids. Light microscopy, ultrastructure, and chemical analysis suggest that the crystalloids represent crystallized salivary alpha-amylase. The inflammatory swelling may mimic benign and/or malignant neoplasms of the salivary glands. Drainage and/or antibiotic therapy may allow surgery to be avoided in these patients.

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Structural relationship between the enzymatic and streptococcal binding sites of human salivary α-amylase

Cited by 61 publications

References 24 publications

Structure of Human Salivary α-Amylase at 1.6 Å Resolution: Implications for its Role in the Oral Cavity

Structure of Human Salivary α-Amylase at 1.6 Å Resolution: Implications for its Role in the Oral Cavity

Structure-function relationships in human salivary α-amylase: role of aromatic residues in a secondary binding site

Sialadenitis with crystalloid formation: A report of six cases diagnosed by fine‐needle aspiration

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