Synonyms for sialosyl or Related words with sialosyl
Examples of "sialosyl"
The unsaturated sialic acid (N-acetylneuraminic acid [Neu5ac]) derivative 2-deoxy-2, 3-didehydro-D-N-acetylneuraminic acid (Neu5Ac2en), a
cation transition-state (Figure 2) analogue, is believed the most potent inhibitor core template. Structurally modified Neu5Ac2en derivatives may give more effective inhibitors.
Endo-alpha-sialidase (, "endo-N-acylneuraminidase", "endoneuraminidase", "endo-N-acetylneuraminidase", "poly(alpha-2,8-
) endo-N-acetylneuraminidase", "poly(alpha-2,8-sialoside) alpha-2,8-sialosylhydrolase", "endosialidase", "endo-N") is an enzyme with systematic name "polysialoside (2->8)-alpha-sialosylhydrolase". This enzyme catalyses the following chemical reaction:
The mechanism of NA has been shown to proceed with the retention of configuration which means it preserves the absolute configuration on the atom in the stereocenter. There are four steps of catalytic pathways. In the first step, the binding step, the carboxylate group changes from the axial position into the pseudo-equatorial position. The second step is the proton donation from water molecule and formation of the endocyclic
cation transition-state intermediate. Step three involves nucleophilic attack of tyrosine on the
cation. The fourth step is the formation and release of Neu5Ac. A similar mechanism has been proposed by Janakiraman et al. where the double bond of Neu5Ac2en forces the pyranose of sugar ring into a planar structure were resembled the transition-state structure.
The enzymatic mechanism of influenza virus sialidase has been studied by Taylor et al., shown in Figure 1. The enzyme catalysis process has four steps. The first step involves the distortion of the α-sialoside from a C chair conformation (the lowest-energy form in solution) to a pseudoboat conformation when the sialoside binds to the sialidase. The second step leads to an oxocarbocation intermediate, the
cation. The third step is the formation of Neu5Ac initially as the α-anomer, and then mutarotation and release as the more thermodynamically-stable β-Neu5Ac.
Influenza virus neuraminidase (vNEU) consists of 4 co-planar roughly spherical subunits predominantly made of β-sheets, characterized as a 6-fold β-propeller and a hydrophobic region embedded in the virus’ membrane. The active site is located near the middle of the pseudo-symmetric sphere. Influenza virus neuraminidase only cleaves terminal Neu5Ac residues. X-ray crystallography has shown a distorted half-chair arrangement of the Neu5Ac substrate in the active site. This distorted structure forms a
cation after the release of the aglycon and is then trapped in the active site by a nucleophilic attack of the tyrosine residue. The orientation of the substrate in the active site is facilitated mainly by three strain-preserved Arginine residues binding the C1 acid group with salt bridges. Furthermore, the active site consists of eight other highly conserved amino acid-residues that make direct contact to the substrate or its derivatives. Including a glutamic acid residue binding the C7 and C9 alcohol groups on the glycerol side-chain (at C6) with hydrogen bonds and several hydrophobic residues correlating with the methyl group on the C5 N-acetyl and the hydrophobic backbone of the glycerol.
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