Biomaterial Database

Positive charges in the cytoplasmic domain of Escherichia coli leader peptidase prevent an apolar domain from functioning as a signal. 1989

J K Laws, and R E Dalbey

Department of Chemistry, Ohio State University, Columbus 43210.

Leader peptidase, an integral transmembrane protein of Escherichia coli, requires two apolar topogenic elements for its membrane assembly: a 'hydrophobic helper' and an internal signal. The highly basic cytoplasmic region between these domains is a translocation poison sequence, which we have shown blocks the function of a preceding signal sequence. We have used oligonucleotide-directed mutagenesis to remove positively charged residues within this polar domain to determine if it is the basic character in this region that has the negative effect on translocation. Our results show that mutations that remove two or more of the positively charged residues within the polar region no longer block membrane assembly of leader peptidase. In addition, when the translocation poison domain (residues 30-52) is replaced with six lysine residues, the preceding apolar domain cannot function as an export signal, whereas it can with six glutamic acids. Thus, positively charged residues within membrane proteins may have a major role in determining the function of hydrophobic domains in membrane assembly.

UI	MeSH Term	Description	Entries
D008565	Membrane Proteins	Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.	Cell Membrane Protein,Cell Membrane Proteins,Cell Surface Protein,Cell Surface Proteins,Integral Membrane Proteins,Membrane-Associated Protein,Surface Protein,Surface Proteins,Integral Membrane Protein,Membrane Protein,Membrane-Associated Proteins,Membrane Associated Protein,Membrane Associated Proteins,Membrane Protein, Cell,Membrane Protein, Integral,Membrane Proteins, Integral,Protein, Cell Membrane,Protein, Cell Surface,Protein, Integral Membrane,Protein, Membrane,Protein, Membrane-Associated,Protein, Surface,Proteins, Cell Membrane,Proteins, Cell Surface,Proteins, Integral Membrane,Proteins, Membrane,Proteins, Membrane-Associated,Proteins, Surface,Surface Protein, Cell
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D010450	Endopeptidases	A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.	Endopeptidase,Peptide Peptidohydrolases
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D012697	Serine Endopeptidases	Any member of the group of ENDOPEPTIDASES containing at the active site a serine residue involved in catalysis.	Serine Endopeptidase,Endopeptidase, Serine,Endopeptidases, Serine
D021382	Protein Sorting Signals	Amino acid sequences found in transported proteins that selectively guide the distribution of the proteins to specific cellular compartments.	Leader Signal Peptides,Leader Peptide,Leader Sequences, Peptide,Peptide Leader Sequences,Peptide Signal Sequences,Signal Peptide,Signal Peptides,Signal Sequence, Peptide,Signal Sequences,Signal Sequences, Peptide,Leader Peptides,Leader Sequence, Peptide,Leader Signal Peptide,Peptide Leader Sequence,Peptide Signal Sequence,Peptide, Leader,Peptide, Leader Signal,Peptide, Signal,Peptides, Leader,Peptides, Leader Signal,Peptides, Signal,Protein Sorting Signal,Sequence, Peptide Leader,Sequence, Peptide Signal,Sequence, Signal,Sequences, Peptide Leader,Sequences, Peptide Signal,Sequences, Signal,Signal Peptide, Leader,Signal Peptides, Leader,Signal Sequence,Signal, Protein Sorting,Signals, Protein Sorting,Sorting Signal, Protein,Sorting Signals, Protein