Copper-zinc superoxide dismutase of Caulobacter crescentus: Cloning, sequencing, and mapping of the gene and periplasmic location of the enzyme

Journal Article · Fri Jun 01 04:00:00 EDT 1990 · Journal of Bacteriology; (USA)

OSTI ID:6532081

Steinman, H M ^[1]; Ely, B ^[2]

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1. Albert Einstein College of Medicine, Bronx, NY (USA)
2. Univ. of South Carolina, Columbia (USA)

To investigate the function of the copper-zinc form of superoxide dismutase (CuZnSOD) (and its structural relationship to the eucaryotic CuZnSoDs) in the freshwater bacterium Caulobacter crecentus, the gene encoding CuZnSOD (sodC) of C. crescentus CB15 was cloned and sequenced. By hybridization to pulsed-field electrophoresis gels, sodC was mapped near cysE in the C. crescentus chromosome. Through analysis of spheroplasts, the two SODs of C. crescentus were shown to be differently localized, CuZnSOD in the periplasm and FeSOD in the cytoplasm. In its natural habitat, C. crescentus is frequently associated with blue-green algae (cyanobacteria). The oxygen evolved by these photosynthetic algae may create an extracellular oxidative stress against which the periplasmic CuZnSOD may defend more effectively than the cytoplasmic FeSOD. Amino acid sequence alignments of C. crescentus CuZnSOD with eucaryotic CuZnSODs and with CuZnSOD of Photobacterium leiognathi (the only other bacterium from which CuZnSOD has been isolated and sequenced) suggest similar supersecondary structures for bacterial and eucaryotic CuZnSODs but reveal four novel substitutions in C. crescentus CuZnSOD: a phenylalanine critical to intrasubunit hydrophobic bonding replaced by alanine, a histidine ligand of zinc replaced by aspartate, and substitutions of two other previously invariant residues that stabilize zinc or both copper and zinc.

• OSTI ID: 6532081
• Journal Information: Journal of Bacteriology; (USA), Journal Name: Journal of Bacteriology; (USA) Vol. 172:6; ISSN JOBAA; ISSN 0021-9193
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
550400 -- Genetics
59 BASIC BIOLOGICAL SCIENCES
BACTERIA
CLONING
COPPER
CYANOBACTERIA
DNA HYBRIDIZATION
DNA SEQUENCING
DNA-CLONING
ELEMENTS
ENZYMES
GENES
GENETIC MAPPING
HYBRIDIZATION
MAPPING
METALS
MICROORGANISMS
MOLECULAR BIOLOGY
OXIDOREDUCTASES
STRUCTURAL CHEMICAL ANALYSIS
SUPEROXIDE DISMUTASE
TRANSITION ELEMENTS
ZINC