Showing papers by "B. de Kruijff published in 1989"
TL;DR: It is suggested that lipid-protein interactions contribute to targeting the precursor toward mitochondria and are important for its translocation across the outer mitochondrial membrane and the final localization of cytochrome c toward the outside of the inner mitochondrial membrane.
93 citations
TL;DR: In this in vitro system SecB and not trigger factor could stabilize a translocation-competent state of prePhoE, and translocation competency of proOmpA could be induced by both trigger factor and SecB protein, suggesting specificity in interactions between cytosolic factors and precursors in outer membrane protein translocation.
63 citations
TL;DR: Binding experiments showed that fragments of apocytochrome c with the highest net positive charge have the highest affinity for negatively charged large unilamellar phosphatidylserine vesicles, and Implications of these data for the import of apoc tochrome c into mitochondria will be discussed.
62 citations
TL;DR: It is shown that coupling of a charged group on either NH2- or COOH-terminus or elongation of the peptide by two amino acids, only slightly affects the surface area characteristics whereas modification of the tryptophans or even replacement of a singletryptophan by phenylalanine leads to drastic alterations in the surface-area characteristics.
41 citations
TL;DR: Binding of the proteins increased the outer hyperfine splitting in the ESR spectra of the lipid spin labees to an extent which depended both on the spin-labelled lipid species involved and on the particular protein, as well as the relative association constants of the different labels with the different proteins have been estimated.
29 citations
TL;DR: Findings suggest that both the carboxy- and amino-terminal parts of the protein penetrate into the center of the bilayer and cause a strong perturbation of the fatty acyl chain motion, which is important for the mechanism of apocytochrome c translocation across membranes.
Abstract: The contribution of the various regions of the mitochondrial precursor protein apocytochrome c to the interaction of the protein with phosphatidylserine dispersions has been studied with chemically and enzymatically prepared fragments of horse heart apocytochrome c and phospholipids spin-labeled at different positions of the sn-2 chain Three amino-terminal heme-less peptides, two heme-containing amino-terminal fragments, one central fragment, and three carboxy-terminal fragments were studied The electron spin resonance spectra of phospholipids spin-labeled at the C5 position of the fatty acid chain indicate that both amino-terminal and carboxy-terminal fragments of the apocytochrome c molecule cause a restriction of motion of the lipids, whereas the heme-containing peptides and protein have less effect In addition, a second motionally more restricted lipid component, which is observed for apocytochrome c interacting with phosphatidylserine dispersions containing lipids spin-labeled at the C12 or C14 position [Gorrissen, H, Marsh, D, Rietveld, A, & de Kruijff, B (1986) Biochemistry 25, 2904-2910], was observed both on binding the carboxy-terminal fragments and on binding of the amino-terminal fragments of the precursor protein Interestingly, even a small water-soluble peptide consisting of the 24 carboxy-terminal residues gave rise to a two-component spectrum, with an outer hyperfine splitting of the restricted lipid component of 59 G, indicating a considerable restriction of the chain motion This suggests that both the carboxy- and amino-terminal parts of the protein penetrate into the center of the bilayer and cause a strong perturbation of the fatty acyl chain motion The implications of these findings for the mechanism of apocytochrome c translocation across membranes are discussed
28 citations
TL;DR: Hydrophobic model peptides, consisting of 5 or 6 amino acids and carrying a nett positive charge at the amino terminus, exhibit a dramatically increased association with large unilamellar egg-PC vesicles upon application of a valinomycin-induced K+ diffusion potential, negative inside.
20 citations
TL;DR: Results from studying Escherichia coli K-12 mutants with defects in protein export or phospholipid metabolism are in agreement with a postulated role of membrane lipids inprotein export.
Abstract: Summary Several models for the transport of proteins across membranes predict a role for lipids. If these models are correct, then alterations in lipid metabolism may affect protein export and vice versa . We are investigating this possibility by studying Escherichia coli K-12 mutants with defects in protein export or phospholipid metabolism. A temperature-sensitive secA mutant, which is defective in protein export at 42°C, exhibited severe pleiotropic effects on membrane biogenesis. Incubation of this strain at 42°C resulted in the appearance of intracytoplasmic membranes, in alterations in lipopolysaccharide structure and in decreased cardiolipin and C18: 1 fatty acid content. On the other hand, a pgsA mutant which is defective in the synthesis of acidic phospholipids, exhibited a protein export defect when studied in vivo or in vitro . These results are in agreement with a postulated role of membrane lipids in protein export.
10 citations