Dataset Information

Structure-function relationships of membrane-associated GT-B glycosyltransferases.

ABSTRACT: Membrane-associated GT-B glycosyltransferases (GTs) comprise a large family of enzymes that catalyze the transfer of a sugar moiety from nucleotide-sugar donors to a wide range of membrane-associated acceptor substrates, mostly in the form of lipids and proteins. As a consequence, they generate a significant and diverse amount of glycoconjugates in biological membranes, which are particularly important in cell-cell, cell-matrix and host-pathogen recognition events. Membrane-associated GT-B enzymes display two "Rossmann-fold" domains separated by a deep cleft that includes the catalytic center. They associate permanently or temporarily to the phospholipid bilayer by a combination of hydrophobic and electrostatic interactions. They have the remarkable property to access both hydrophobic and hydrophilic substrates that reside within chemically distinct environments catalyzing their enzymatic transformations in an efficient manner. Here, we discuss the considerable progress that has been made in recent years in understanding the molecular mechanism that governs substrate and membrane recognition, and the impact of the conformational transitions undergone by these GTs during the catalytic cycle.

SUBMITTER: Albesa-Jove D

PROVIDER: S-EPMC3907083 | biostudies-literature | 2014 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Structure-function relationships of membrane-associated GT-B glycosyltransferases.

Albesa-Jové David D Giganti David D Jackson Mary M Alzari Pedro M PM Guerin Marcelo E ME

Glycobiology 20131118 2

Membrane-associated GT-B glycosyltransferases (GTs) comprise a large family of enzymes that catalyze the transfer of a sugar moiety from nucleotide-sugar donors to a wide range of membrane-associated acceptor substrates, mostly in the form of lipids and proteins. As a consequence, they generate a significant and diverse amount of glycoconjugates in biological membranes, which are particularly important in cell-cell, cell-matrix and host-pathogen recognition events. Membrane-associated GT-B enzym ...[more]

PMID: 24253765

Similar Datasets

Project description:The crystal structures of the Ca(2+)- and H(+)-ATPases shed light into the membrane embedded domains involved in binding and ion translocation. Consistent with site-directed mutagenesis, these structures provided additional evidence that membrane-spanning segments M4, M5, M6 and M8 are the core through which cations are pumped. In the present study, we have used alanine/serine scanning mutagenesis to study the structure-function relationships within M6 (Leu-721-Pro-742) of the yeast plasma membrane ATPase. Of the 22 mutants expressed and analyzed in secretory vesicles, alanine substitutions at two well conserved residues (Asp-730 and Asp-739) led to a complete block in biogenesis; in the mammalian P-ATPases, residues corresponding to Asp-730 are part of the cation-binding domain. Two other mutants (V723A and I736A) displayed a dramatic 20-fold increase in the IC(50) for inorganic orthovanadate compared to the wild-type control, accompanied by a significant reduction in the K(m) for Mg-ATP, and an alkaline shift in the pH optimum for ATP hydrolysis. This behavior is apparently due to a shift in equilibrium from the E(2) conformation of the ATPase towards the E(1) conformation. By contrast, the most striking mutants lying toward the extracellular side in a helical structure (L721A, I722A, F724A, I725A, I727A and F728A) were expressed in secretory vesicles but had a severe reduction of ATPase activity. Moreover, all of these mutants but one (F728A) were unable to support yeast growth when the wild-type chromosomal PMA1 gene was replaced by the mutant allele. Surprisingly, in contrast to M8 where mutations S800A and E803Q (Guerra et al., Biochim. Biophys. Acta 1768: 2383-2392, 2007) led to a dramatic increase in the apparent stoichiometry of H(+) transport, three substitutions (A726S, A732S and T733A) in M6 showed a reduction in the apparent coupling ratio. Taken together, these results suggest that M6 residues play an important role in protein stability and function, and probably are responsible for cation binding and stoichiometry of ion transport as suggested by homology modeling.

Dataset Information

Structure-function relationships of membrane-associated GT-B glycosyltransferases.

Publications

Structure-function relationships of membrane-associated GT-B glycosyltransferases.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets