Chapter 2 Structure and Function of the Signal Peptide

Duffaud, Guy D.; Lehnhardt, S; March, Paul E.; Inouye, Masayori

doi:10.1016/s0070-2161(08)60324-x

Cited by 80 publications

(45 citation statements)

References 117 publications

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“…In bacteria, proteins destined for secretion are synthesized with amino-terminal signal peptides that typically carry several positively charged residues at the amino-terminal end followed by a hydrophobic stretch of 14 to 20 residues (Duffaud et al, 1985). In fact, the intermediate prepieces of cytochromes b2 and cl have a similar structure.…”

Section: Discussionmentioning

confidence: 99%

Successive translocation into and out of the mitochondrial matrix: Targeting of proteins to the intermembrane space by a bipartite signal peptide

Hartl¹,

Ostermann²,

Guiard

et al. 1987

Cell

270

143

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SummaryWe investigated the import and sorting pathways of cytochrome b2 and cytochrome cl, which are functionally located in the intermembrane space of mitochondria. Both proteins are synthesized on cytoplasmic ribosomes as larger precursors and are processed in mitochondria in two steps upon import. The precursors are first translocated across both mitochondrial membranes via contact sites into the matrix. Processing by the matrix peptidase leads to intermediatesized forms, which art? subsequently redirected across the inner membrane. The second proteolytic processing occurs in the intermembrane space. We conclude that the hydrophobic stretches in the presequences of the intermediate-sizedforms do not stop transfer across the inner membrane, but rather act as transport signals to direct export from the matrix into the intermembrane space.

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Section: Discussionmentioning

confidence: 99%

Successive translocation into and out of the mitochondrial matrix: Targeting of proteins to the intermembrane space by a bipartite signal peptide

Hartl¹,

Ostermann²,

Guiard

et al. 1987

Cell

270

143

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“…These include two positively charged residues (lysines) within the first five amino acids and a stretch of 15 amino acids between the last lysine and the next charged residue exceptions to this hydrophobicity are serine, threonine, and glycine residues, and these are located in positions commonly occupied by these residues in the hydrophobic domain of signal peptides (4 (Fig. 2 and 3).…”

Section: Resultsmentioning

confidence: 99%

Mapping, sequence, and apparent lack of function of araJ, a gene of the Escherichia coli arabinose regulon

Reeder

Schleif

1991

J Bacteriol

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We report the mapping, sequencing, and study of the physiological role of the fourth arabinose-inducible operon from Escherichia coli, araJ. It is located at 9 min on the chromosome and codes for a single 42-kDa protein that shows no significant homology to other known proteins. Destruction of the chromosomal araJ gene does not detectably affect either of the two arabinose transport systems, the ability of cells to grow The enteric bacterium Escherichia coli can utilize L-arabinose as a sole carbon source. In the presence of arabinose, expression from the three known ara operons is induced up to 300-fold. These are the araBAD operon (5, 6), which codes for proteins involved in the catabolism of arabinose, and the araE (27) and araFGH (2, 17, 31) operons, which code for the low-and high-affinity arabinose transport systems, respectively: In addition to the promoters of these three well-characterized operons, there exists a fourth promoter in E. coli that is induced by arabinose. This promoter was originally cloned by Kosiba and Schleif (18) and at that time was misidentified as the araFGH promoter. Subsequent work (11, 13) has identified the actual araFGH promoter, and the arabinose-inducible promoter cloned by Kosiba and Schleif (18) is now known as pJ. Recent work (11,18) has shown that arabinose induces substantial transcription from pJ in vivo and in vitro. In vivo, as well as in vitro (11,18), transcription from pJ is dependent upon the arabinosespecific transcriptional regulator protein AraC and the global catabolite gene activator protein CAP, as is transcription from the araBAD, araE, and araFGH operons (7,8,32).Since all known ara mutations are confined to the araBAD, araC, araE, and araFGH operons, we were interested to learn whether pJ drives an intact gene and whether its product plays any detectable role in vivo. In particular, we wished to determine whether the araJ product was a fourth component in the high-affinity arabinose transport system, since most analogous systems contain four protein components (1, 34).Here we report the mapping of the araJ gene to 9 min on the E. coli chromosome and the cloning and sequencing of the araJ gene and surrounding regions of the chromosome. We also show that insertion/deletion mutations in araJ have no detectable effect on the ability of the bacteria to grow on arabinose and to induce the araBAD operon. MATERIALS AND METHODSMedia, strains, and general methods. Media and general methods have been described (21,33 Kosiba and Schleif (18) containing the araJ promoter. Three positive clones were selected and shown by restriction mapping to contain overlapping copies of the same piece of genomic DNA; these three clones were sent to us for further analysis.One of the lambda clones was digested with PvuI, and the 1.9-and 2.5-kb fragments that contained pJ and flanking sequences were isolated. The fragments were filled out with DNA polymerase (Klenow fragment) and then ligated into 7765 JOURNAL OF BACTERIOLOGY, Dec. 1991, p. 7765-7771

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“…Furthermore, the Gene X signal sequence contains a glutamic acid residue in the 17th position, although the absence of charged amino acids in front of this position allows this sequence to meet a minimum hydrophobic-core requirement of approximately 12 amino acid residues (3). The protein sequence up to this region is rich in two amino acid residues, leucine and alanine, which are found preferentially in hydrophobic-core regions of signal peptides (7). Finally, the Gene X signal sequence does contain a potential consensus-processing site, Ala-Lys-Ala (7,33), giving rise to a signal peptide of 23 amino acid residues.…”

Section: Discussionmentioning

confidence: 99%

“…The protein sequence up to this region is rich in two amino acid residues, leucine and alanine, which are found preferentially in hydrophobic-core regions of signal peptides (7). Finally, the Gene X signal sequence does contain a potential consensus-processing site, Ala-Lys-Ala (7,33), giving rise to a signal peptide of 23 amino acid residues. While it is tempting to speculate that these features of the Gene X signal peptide may be significant in delaying the export of this protein and in allowing it to play some role in modulating the protein export process itself, we have yet to obtain any evidence for such a role.…”

Section: Discussionmentioning

confidence: 99%

The first gene in the Escherichia coli secA operon, gene X, encodes a nonessential secretory protein

1991

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TnphoA insertions in the first gene of the Escherichia coli secA operon, gene X, were isolated and analyzed. Studies of the Gene X-PhoA fusion proteins showed that gene X encodes a secretory protein, since the fusion proteins possessed normal alkaline phosphatase activity and a substantial portion of this activity was found in the periplasm. In addition, the Gene X-PhoA fusion proteins were initially synthesized with a cleavable signal peptide. A gene X::TnphoA insertion was used to construct a strain containing a disrupted chromosomal copy of gene X. Analysis of this strain indicated that gene X is nonessential for cell growth and viability and does not appear to play an essential role in the process of protein export.

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Chapter 2 Structure and Function of the Signal Peptide

Cited by 80 publications

References 117 publications

Successive translocation into and out of the mitochondrial matrix: Targeting of proteins to the intermembrane space by a bipartite signal peptide

Successive translocation into and out of the mitochondrial matrix: Targeting of proteins to the intermembrane space by a bipartite signal peptide

Mapping, sequence, and apparent lack of function of araJ, a gene of the Escherichia coli arabinose regulon

The first gene in the Escherichia coli secA operon, gene X, encodes a nonessential secretory protein

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