Mechanism and Stereoelectronic Effects in the Lysozyme Reactio

Kirby, Anthony J.

doi:10.3109/10409238709086959

Cited by 69 publications

(46 citation statements)

References 74 publications

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“…The requirement for the precise positioning of the carboxyl group indicates that residue 53 contributes more than a simple electrostatic stabilization of the intermediate oxo-carbonium ion. The carboxyl group may be involved in a geometrically constrained interaction with the substrate, such as the formation of an incomplete covalent bond (Kirby, 1987).…”

Section: A) As Shown Inmentioning

confidence: 99%

“…This interpretation for the role of the Asp residue has been widely accepted. However, another model has suggested the possibility that the carboxyl group acts as a nucleophile to form a covalent intermediate (Kirby, 1987). Although there has been no direct evidence for the intermediate compound, the proposed models have stressed the importance of the ionized carboxyl group of the Asp residue.…”

mentioning

confidence: 99%

“…Since the three-dimensional structure of chicken lysoiyme (CL) has been revealed by X-ray analysis (Blake et al, 1965), the catalytic properties of the enzyme have been extensively studied in relation to the geometry of the active site and substrate binding (Imoto et al, 1972;Jollks & Jollb, 1984;Kirby, 1987). The active site of the CLs consists of six subsites for sugar binding, which are designated A-E The active center is located in between the D and E subsites.…”

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confidence: 99%

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X‐ray structure of glu 53 human lysozyme

et al. 1992

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The three-dimensional structure of a modified human lysozyme (HL), Glu 53 HL, in which Asp 53 was replaced by Glu, has been determined at 1.77 A resolution by X-ray analysis. The backbone structure of Glu 53 HL is essentially the same as the structure of wild-type HL. The root mean square difference for the superposition of equivalent C" atoms is 0.141 A. Except for the Glu 53 residue, the structure of the active site region is largely conserved between Glu 53 HL and wild-type HL. However, the hydrogen bond network differs because of the small shift or rotation of side chain groups. The carboxyl group of Glu 53 points to the carboxyl group of Glu 35 with a distance of 4.7 A between the nearest carboxyl oxygen atoms. A water molecule links these carboxyl groups by a hydrogen bond bridge. The active site structure explains well the fact that the binding ability for substrates does not significantly differ between Glu 53 HL and wild-type HL. On the other hand, the positional and orientational change of the carboxyl group of the residue 53 caused by the mutation is considered to be responsible for the low catalytic activity (ca. 1070) of Glu 53 HL. The requirement of precise positioning for the carboxyl group suggests the possibility that the Glu 53 residue contributes more than a simple electrostatic stabilization of the intermediate in the catalysis reaction.

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Section: A) As Shown Inmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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X‐ray structure of glu 53 human lysozyme

et al. 1992

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“…The PROSITE data bank uses this region as a signature pattern. Based on mechanism studies with lysozyme [22] *Partial sequence hydrolysis of P-glycosidic bonds is considered to proceed by general acid catalysis involving aspartic and glutamic acid residues. In the case of lysozyme, Glu-35 promotes catalysis by promoting the glycosyl oxygen, while the carboxylate form of Asp-52 stabilizes the glycosyl carbonium ion intermediate [22].…”

Section: Fig 1 (Cord)mentioning

confidence: 99%

“…Based on mechanism studies with lysozyme [22] *Partial sequence hydrolysis of P-glycosidic bonds is considered to proceed by general acid catalysis involving aspartic and glutamic acid residues. In the case of lysozyme, Glu-35 promotes catalysis by promoting the glycosyl oxygen, while the carboxylate form of Asp-52 stabilizes the glycosyl carbonium ion intermediate [22]. Conceivably, the aspartic amino acid residue of the SDW motif, as well as the conserved Glu residue nine amino acids upstream, could fulfill a function similar to Asp and Glu of lysozyme.…”

Section: Fig 1 (Cord)mentioning

confidence: 99%

A sequence analysis of the β‐glucosidase sub‐family B

Rojas

Romeu

1996

FEBS Letters

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This computational study is a summary of structural properties of the fi-glucosidase subfamily B. Computations were carried out using GCG package programs. All sequences used in this analysis were taken from the protein data bank. The multialignment and the phylogenetic tree of the P-glucosidase subfamily B are shown. The conserved patterns: DGP, GRNFE, DPYL, KHF, SDW, GLD, VLLKN in the N-terminal region and FGYGLSY in the C-terminal part should be pointed out. Cterminal parts of the ButyrivibrioJibrisolvens and Ruminoccocus albus @-glucosidase sequences can be aligned to the N-terminal region of the other members of the subfamily. A crossed homology model in sub-family B P-glucosidases is described.

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