prlA-mediated suppression of signal sequence mutations is modulated by the secA gene product of Escherichia coli K-12

Oliver, Donald B.; Liss, L R

doi:10.1128/jb.161.2.817-819.1985

Cited by 16 publications

(1 citation statement)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Products of these two genes were suggested to be assembled in a complex (Bankaitis and Bassford, 1985a). Extragenic suppressor mutations also suggested involvement of sec A, prl A, sec C, and other loci in protein translocation in E. coli which would possess a general mechanism of coupling of synthesis of exported proteins with secretion (Oliver, 1985;Oliver and Liss, 1985). Both prl A and sec A gene products were implicated in the indirect binding of ribosomes involved in the synthesis of exported proteins to the membrane (Rasmussen and Bassford, 1985).…”

Section: Bacterial Membrane Proteinsmentioning

confidence: 99%

Reconstitution and Physiological Protein Translocation Processes

Etemadi

1989

Subcellular Biochemistry

View full text Add to dashboard Cite

FIGURE 1. Some models for membrane-protein interaction during translocation of secretory and! or transmembrane integral proteins are reproduced. In all schemes, unless otherwise stated, the lower side and the upper side represent the cytoplasmic (cis) and the extracytoplasmic (trans) compartment, respectively. In the loop model A (DiRienzo et al. 1978;Inouye and Halegoua 1980), positively charged amino acid(s) at the N terminus of the signal sequence react with negatively charged head groups of membrane phospholipids. The hydrophobic part of the signal sequence would interact with and loop back in the hydrophobic core of the membrane, bending being due to the presence of a glycine or proline residue in the hydrophobic segment of the signal. Chain elongation would continue until the cleavage site reaches the side remote from the cytoplasm where processing occurs. In model B (Garnier et at., 1980) the signal sequence as a double amphipathic structure inserts in the membrane. Its hydrophobic core has an a-helical or extended conformation and its N terminus is extracytoplasmic. Only after this insertion ribophorin (R) assembly around the signal peptide occurs and interaction of ribophorins, with the ribosomes, leads to the formation of a channel through which the protein is translocated. In the helical hairpin model, C (Engelman and Steitz, 1981), the signal sequence and the N-terminal segment of the mature part of a nascent secretory or transmembrane integral protein form a hydrophobic (H) and a polar (P) helix, respectively, which together exhibit a helical hairpin conformation. The "helical hairpin" is inserted into the membrane in such a way that the N terminus of the signal sequence is cytoplasmic, as in the loop model. Continuation of translation extrudes residues of the polar helix in the trans side, while

show abstract

Section: Bacterial Membrane Proteinsmentioning

confidence: 99%

Reconstitution and Physiological Protein Translocation Processes

Etemadi

1989

Subcellular Biochemistry

View full text Add to dashboard Cite

show abstract

ProOmpA spontaneously folds in a membrane assembly competent state which trigger factor stabilizes.

et al. 1988

View full text Add to dashboard Cite

The precursor protein proOmpA can translocate across purified Escherichia coli inner membrane vesicles in the absence of any other soluble proteins. ProOmpA, purified 2000‐fold in the presence of 8 M urea, is competent for translocation following rapid renaturation via dilution. ATP, the transmembrane electrochemical potential, and functional secY protein are essential for the translocation of proOmpA renatured by dilution. The kinetics of its translocation and the level of translocation at each concentration of ATP are indistinguishable from that of proOmpA renatured by dialysis with trigger factor. After dilution, the proOmpA rapidly loses its competence for membrane assembly. However, this competence is stabilized by trigger factor. Assembly‐competent proOmpA is in a protease‐sensitive conformation, whereas proOmpA which has lost this competence is more resistant to degradation. This suggests that the primary role for trigger factor in in vitro protein translocation is to maintain precursor proteins in a translocation‐competent conformation. We propose that a properly folded precursor protein and ATP are the only soluble components which are essential for bacterial protein translocation.

show abstract

Protein translocationin vitro: Biochemical characterization of genetically defined translocation components

Fandl

Tai

1990

J Bioenerg Biomembr

View full text Add to dashboard Cite

Recent years have seen the convergence of both genetic and biochemical approaches in the study of protein translocation in E. coli. The powerful combination of these approaches is exemplified in the use of an in vitro protein synthesis-protein translocation system to analyze the role of genetically defined components of the protein translocation machinery. We describe in this review recent results focusing on the function of the secA, secB, and secY gene products and the demonstration of their requirement for in vitro protein translocation. The SecA protein was recently shown to possess ATPase activity and was proposed to be a component of the translocation ATPase. We present a speculative working model whereby the translocator complex is composed of the integral membrane proteins SecY, SecD, SecE, and SecF, forming an aqueous channel in the cytoplasmic membrane, and the tightly associated peripheral membrane protein SecA functioning as the catalytic subunit of the translocator or "protein-ATPase."

show abstract

prlA-mediated suppression of signal sequence mutations is modulated by the secA gene product of Escherichia coli K-12

Cited by 16 publications

References 11 publications

Reconstitution and Physiological Protein Translocation Processes

Reconstitution and Physiological Protein Translocation Processes

ProOmpA spontaneously folds in a membrane assembly competent state which trigger factor stabilizes.

Protein translocationin vitro: Biochemical characterization of genetically defined translocation components

Contact Info

Product

Resources

About