Biomedical subjects

Guy Vandenbussche

Publications and source records attributed to Guy Vandenbussche.

4 recordsLinked to original sources

PubMed2006

Affinity chromatography: a useful tool in proteomics studies.

Separation or fractionation of a biological sample in order to reduce its complexity is often a prerequisite to qualitative or quantitative proteomic approaches. Affinity chromatography is an efficient protein separation method based on the interaction between target proteins and specific immobilized ligands. The large range of available ligands allows to separate a complex biological extract in different protein classes or to isolate the low abundance species such as post-translationally modified proteins. This method plays an essential role in the isolation of protein complexes and in the identification of protein-protein interaction networks. Affinity chromatography is also required for quantification of protein expression by using isotope-coded affinity tags.

Chromatography, Affinity↗

PubMed2006

The SlyB outer membrane lipoprotein of Burkholderia multivorans contributes to membrane integrity.

SlyB is a small lipoprotein of 158 amino acids which is conserved in different Gram-negative bacteria. In contrast to other bacteria, where slyB is monocistronic, in Burkholderia multivorans and in B. cenocepacia, slyB is the last gene of an operon comprising three open reading frames encoding a putative thiol peroxidase, a putative sugar kinase and SlyB. B. multivorans slyB mutants produced elongated cells and filaments which were never observed in cultures of wild-type or slyB-complemented cells. The slyB mutant also showed increased sensitivity to EDTA and SDS, and decreased siderophore production. Proteome analysis of a fraction enriched for membrane proteins suggested that SlyB, like the peptidoglycan-associated protein OpcL, is a major protein of the outer membrane. Taken together, these phenotypes suggest that SlyB contributes to the integrity of the cell envelope. By PCR amplification we were also able to demonstrate the conservation of slyB in all B. cepacia complex species tested.

Amino Acid Sequence↗

PubMed2005

Crystallization and crystal manipulation of a steric chaperone in complex with its lipase substrate.

Bacterial lipases that are secreted via the type II secretion pathway require a lipase-specific foldase in order to obtain their native and biologically active conformation in the periplasmic space. The lipase-foldase complex from Burkholderia glumae (319 and 333 residues, respectively) was crystallized in two crystal forms. One crystal form belongs to space group P3(1)21 (P3(2)21), with unit-cell parameters a = b = 122.3, c = 98.2 A. A procedure is presented which improved the diffraction of these crystals from approximately 5 to 2.95 A. For the second crystal form, which belonged to space group C2 with unit-cell parameters a = 183.0, b = 75.7, c = 116.6 A, X-ray data were collected to 1.85 A.

Bacterial Proteins↗

PubMedDate not supplied

Charged residues are involved in membrane fusion mediated by a hydrophilic peptide located in vesicular stomatitis virus G protein.

Membrane fusion is an essential step of the internalization process of the enveloped animal viruses. Vesicular stomatitis virus (VSV) infection is mediated by virus spike glycoprotein G, which induces membrane fusion at the acidic environment of the endosomal compartment. In a previous work, we identified a specific sequence in VSV G protein, comprising the residues 145 to 164, directly involved in membrane interaction and fusion. Unlike fusion peptides from other viruses, this sequence is very hydrophilic, containing six charged residues, but it was as efficient as the virus in catalyzing membrane fusion at pH 6.0. Using a carboxyl-modifying agent, dicyclohexylcarbodiimide (DCCD), and several synthetic mutant peptides, we demonstrated that the negative charges of peptide acidic residues, especially Asp153 and Glu158, participate in the formation of a hydrophobic domain at pH 6.0, which is necessary to the peptide-induced membrane fusion. The formation of the hydrophobic region and the membrane fusion itself were dependent on peptide concentration in a higher than linear fashion, suggesting the involvement of peptide oligomerization. His148 was also necessary to hydrophobicity and fusion, suggesting that peptide oligomerization occurs through intermolecular electrostatic interactions between the positively-charged His and a negatively-charged acidic residue of two peptide molecules. Oligomerization of hydrophilic peptides creates a hydrophobic region that is essential for the interaction with the membrane that results in fusion.

Amino Acid Sequence↗