Serratia proteamaculans

Taxonomy

Microphotography S.proteamaculans 
   cellular organisms
     domain Bacteria
        group Proteobacteria
          class Gammaproteobacteria
            order Enterobacteriales
              family Enterobacteriaceae
                genus Serratia
                  species Serratia proteamaculans

Description

Serratia proteamaculans is a Gram-negative, facultatively anaerobic, rod-shaped bacterium.
Serratia proteamaculans 568, an Enterobacteriaceae, was isolated as a root endophyte from Populus trichocarpa. S.proteamaculans has been found promote plant growth, and it has been demonstrated that this occurs via the production of specific compounds, such as lipo-chitin oligosaccharides, which are used as specific bacteria-to-plant signals. Individual plant growth promoting bacteria produce specific structurally diverse LCO mixtures. Endophytes are bacteria that live within the tissue of a plant without substantively harming it. They can help promote plant growth in several ways, including helping the host overcome toxic effects of environmental pollution.

The sequencing of S. proteamaculans 568 genome provided an ideal basis to study bacteria to plant signaling of this bacterium and its poplar host

Chitinases of Serratia proteamaculans

Serratia proteamaculans 568 genome revealed the presence of four family 18 chitinases (Sp ChiA, Sp ChiB, Sp ChiC, and Sp ChiD). Heterologous expression and characterization of Sp ChiA, Sp ChiB, and Sp ChiC showed that these enzymes were optimally active at pH 6.0-7.0, and 40°C. The three Sp chitinases displayed highest activity/binding to ß- chitin and showed broad range of substrate specificities, and released dimer as major end product from oligomeric and polymeric substrates. Longer incubation was required for hydrolysis of trimer for the three Sp chitinases. The three Sp chitinases released up to tetramers from colloidal chitin substrate. Sp ChiA and Sp ChiB were processive chitinases, while Sp ChiC was a non-processive chitinase. Based on the known structures of ChiA and ChiB from S. marcescens, 3D models of Sp ChiA and Sp ChiB were generated.

Genome and proteome

Serratia proteamaculans has one chromosome and one plasmid (see table 1 for characteristics).

Table 1
Component name Protein count Type Length (bp) Av. CDS Length GC content CDS coverage Gene count
Chromosome 4891 ring 5448853 972.086 55.1% 87% 4891
Plasmid pSPRO01 51 ring 46804 677.176 49.2% 74% 51

The most usable codon in chromosome is CTG, in plasmid it is GAA. You can find full information in diagrams 1 and 2.

Diagram 1. Triplet usage in chromosome Diagram 2. Triplet usage in plasmid

The most widespread aminoacid in proteins of S. proteamaculans is leucine, alanine and glycine (diagram 3). Most proteins are composed of 100-500 amino-acids (diagram 4).

Diagram 3. Amino acid composition Diagram 4. Protein length distribution

Sources