Biomaterial Database

Cloning and characterization of the genes coding for two porins in the unicellular cyanobacterium Synechococcus PCC 6301. 1998

A Hansel, and F Pattus, and U J Jürgens, and M H Tadros

Institut für Biologie II/Mikrobiologie, Albert-Ludwigs-Universität Freiburg, Germany.

The genes somB and somA (Synechococcus outer membrane), lying in tandem organization in the genome of Synechococcus PCC 6301, encode two porins in the outer membrane of this unicellular cyanobacterium. Northern blot and primer extension experiments revealed that somA and somB are not comprising an operon, as each gene encodes a transcript of 1.7 kb length and has a distinct transcriptional start site. The deduced SomA and SomB protein sequences include typical N-terminal signal peptides and reveal 60% homology (50% identical residues) to each other as well as significant homology to six protein sequences deduced from open reading frames sequenced in the genome of the unicellular cyanobacterium Synechocystis PCC 6803. Furthermore, SomA possesses an overall identity of 97% to the functionally not yet characterized outer-membrane protein SomA from the closely related cyanobacterial strain Synechococcus PCC 7942. Analyses performed on the sequences suggest that SomA and SomB form 14- or 16-stranded porin-like beta-barrels. Moreover, all sequences share an N-terminal motif with significant homology to 'S-layer homology' domains, which might form a periplasmic extension. SomA and SomB therefore may, in addition to their porin function, act as linkers connecting the outer membrane with the peptidoglycan layer.

UI	MeSH Term	Description	Entries
D008562	Membrane Glycoproteins	Glycoproteins found on the membrane or surface of cells.	Cell Surface Glycoproteins,Surface Glycoproteins,Cell Surface Glycoprotein,Membrane Glycoprotein,Surface Glycoprotein,Glycoprotein, Cell Surface,Glycoprotein, Membrane,Glycoprotein, Surface,Glycoproteins, Cell Surface,Glycoproteins, Membrane,Glycoproteins, Surface,Surface Glycoprotein, Cell,Surface Glycoproteins, 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
D002874	Chromosome Mapping	Any method used for determining the location of and relative distances between genes on a chromosome.	Gene Mapping,Linkage Mapping,Genome Mapping,Chromosome Mappings,Gene Mappings,Genome Mappings,Linkage Mappings,Mapping, Chromosome,Mapping, Gene,Mapping, Genome,Mapping, Linkage,Mappings, Chromosome,Mappings, Gene,Mappings, Genome,Mappings, Linkage
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D000458	Cyanobacteria	A phylum of oxygenic photosynthetic bacteria comprised of unicellular to multicellular bacteria possessing CHLOROPHYLL a and carrying out oxygenic PHOTOSYNTHESIS. Cyanobacteria are the only known organisms capable of fixing both CARBON DIOXIDE (in the presence of light) and NITROGEN. Cell morphology can include nitrogen-fixing heterocysts and/or resting cells called akinetes. Formerly called blue-green algae, cyanobacteria were traditionally treated as ALGAE.	Algae, Blue-Green,Blue-Green Bacteria,Cyanophyceae,Algae, Blue Green,Bacteria, Blue Green,Bacteria, Blue-Green,Blue Green Algae,Blue Green Bacteria,Blue-Green Algae
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
D001426	Bacterial Proteins	Proteins found in any species of bacterium.	Bacterial Gene Products,Bacterial Gene Proteins,Gene Products, Bacterial,Bacterial Gene Product,Bacterial Gene Protein,Bacterial Protein,Gene Product, Bacterial,Gene Protein, Bacterial,Gene Proteins, Bacterial,Protein, Bacterial,Proteins, Bacterial
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D015870	Gene Expression	The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.	Expression, Gene,Expressions, Gene,Gene Expressions
D016415	Sequence Alignment	The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.	Sequence Homology Determination,Determination, Sequence Homology,Alignment, Sequence,Alignments, Sequence,Determinations, Sequence Homology,Sequence Alignments,Sequence Homology Determinations