Novel prlA alleles defective in supporting staphylokinase processing in Escherichia coli

Sako, Tomoyuki

doi:10.1128/jb.173.7.2289-2296.1991

Cited by 19 publications

(12 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also, the two haploid-defective alleles contain deletions that remove 11 amino acids from TM7. Based on the isolation and characterization of suppressor mutations that interfere with the function of the staphylokinase signal sequence, Sako (1991) proposed TM7 as the principal domain for signal sequence recognition by SecY. Our data support this view, and we concur.…”

Section: Tm7supporting

confidence: 82%

See 1 more Smart Citation

PrlA suppressor mutations cluster in regions corresponding to three distinct topological domains.

1993

View full text Add to dashboard Cite

The SecY protein of Escherichia coli and its homologues in other organisms, are integral components of the cellular protein translocation machinery. Suppressor mutations that alter SecY (the prlA alleles) broaden the specificity of this machinery and allow secretion of precursor proteins with defective signal sequences. Twenty‐five prlA alleles have been characterized. These suppressor mutations were found to cluster in regions corresponding to three distinct topological domains of SecY. Based on the nature and position of the prlA mutations, we propose that transmembrane domain 7 of SecY functions in signal sequence recognition. Results suggest that this interaction may involve a right‐handed supercoil of alpha‐helices. Suppressor mutations that alter this domain appear to prevent signal sequence recognition, and this novel mechanism of suppression suggests a proofreading function for SecY. We propose that suppressor mutations that alter a second domain of SecY, transmembrane helix 10, also affect this proof‐reading function, but indirectly. Based on the synthetic phenotypes exhibited by double mutants, we propose that these mutations strengthen the interaction with another component of the translocation machinery, SecE. Suppressor mutations were also found to cluster in a region corresponding to an amino‐terminal periplasmic domain. Possible explanations for this unexpected finding are discussed.

show abstract

Section: Tm7supporting

confidence: 82%

“…The remaining two mutations presented in Table I and Figure 1, secY121 and secY161, were isolated and characterized by Sako (1991). These mutations reduce the export of staphylokinase, and although not extensively characterized, appear to have no suppressor activity.…”

Section: Dna Sequence Analysismentioning

confidence: 99%

PrlA suppressor mutations cluster in regions corresponding to three distinct topological domains.

1993

View full text Add to dashboard Cite

show abstract

“…The corresponding region of the Escherichia coli translocon contains three Ser and one Thr groups in the sequence S 281 S 282 IILFPA T 288 IA S 291 (Bondar et al 2010). Mutation of the E. coli S282 to Arg leads to the prl A401 phenotype (Osborne and Silhawy 1993) thought to be characterized by the destabilization of the closed state of the translocon (Smith et al 2005); adding one more Thr that replaces I290 reduced export of staphylokinase by the translocon (Sako 1991; Osborne and Silhavy 1993). Arrangements of Ser/Thr separated by two or three residues, with the Ser/Thr side chains largely on one side of the TM helix, are also observed in the P-type proton pump AHA2 from Arabidopsis thaliana — T 686 IM T 689 , S 762 II S 765 , or S 827 IV T 830 (pdb 3B8C, Pedersen et al 2007); the T 686 IM T 689 segment within TM6 is very close to the primary proton donor/acceptor D684.…”

mentioning

confidence: 99%

Ser/Thr Motifs in Transmembrane Proteins: Conservation Patterns and Effects on Local Protein Structure and Dynamics

2012

View full text Add to dashboard Cite

We combined systematic bioinformatics analyses and molecular dynamics simulations to assess the conservation patterns of Ser and Thr motifs in membrane proteins, and the effect of such motifs on the structure and dynamics of α-helical transmembrane (TM) segments. We find that Ser/Thr motifs are often present in β-barrel TM proteins. At least one Ser/Thr motif is present in almost half of the sequences of α-helical proteins analyzed here. The extensive bioinformatics analyses and inspection of protein structures led to the identification of molecular transporters with noticeable numbers of Ser/Thr motifs within the TM region. Given the energetic penalty for burying multiple Ser/Thr groups in the membrane hydrophobic core, the observation of transporters with multiple membrane-embedded Ser/Thr is intriguing and raises the question of how the presence of multiple Ser/Thr affects protein local structure and dynamics. Molecular dynamics simulations of four different Ser-containing model TM peptides indicate that backbone hydrogen bonding of membrane-buried Ser/Thr hydroxyl groups can significantly change the local structure and dynamics of the helix. Ser groups located close to the membrane interface can hydrogen bond to solvent water instead of protein backbone, leading to an enhanced local solvation of the peptide.

show abstract

“…First, some prlA mutations map within them (Osborne and Silhavy 1993). Thirdly, mutations that alleviate the toxic effects of staphylokinase expression in E. coli have been mapped within TMS7 (Sako 1991). Thirdly, mutations that alleviate the toxic effects of staphylokinase expression in E. coli have been mapped within TMS7 (Sako 1991).…”

Section: Discussionmentioning

confidence: 99%

Importance of transmembrane segments in Escherichia coli SecY

2003

View full text Add to dashboard Cite

To assess the functional importance of the transmembrane regions of SecY, we constructed a series of SecY variants, in which the six central residues of each transmembrane segment were replaced by amino acid residues from either transmembrane segment 3 or 4 of LacY. The SecY function, as assessed by the ability to complement cold-sensitive secY mutants with respect to their growth and translocase defects, was eliminated by the alterations in transmembrane segments 2, 3, 4, 7, 9 and 10. Among them, those in segments 3 and 4 had especially severe effects. In contrast, transmembrane segments 1, 5, 6, and 8 were more tolerant to the sequence alterations. The purified protein with an altered transmembrane segment 6 retained, in large measure, the ability to support SecA-dependent preprotein translocation in vitro. These results will help us to further understand how the SecYEG protein translocation channel functions.

show abstract

Novel prlA alleles defective in supporting staphylokinase processing in Escherichia coli

Cited by 19 publications

References 41 publications

PrlA suppressor mutations cluster in regions corresponding to three distinct topological domains.

PrlA suppressor mutations cluster in regions corresponding to three distinct topological domains.

Ser/Thr Motifs in Transmembrane Proteins: Conservation Patterns and Effects on Local Protein Structure and Dynamics

Importance of transmembrane segments in Escherichia coli SecY

Contact Info

Product

Resources

About