The role of a 2-on-2 haemoglobin in oxidative and nitrosative stress resistance of Antarctic Pseudoalteromonas haloplanktis TAC125.
The 2-on-2 haemoglobins, previously named truncated, are monomeric, low-molecular weight oxygen-binding proteins that share the overall topology with vertebrate haemoglobins. Although several studies on 2-on-2 haemoglobins have been reported, their physiological and biochemical functions are not yet well defined, and various roles have been suggested. The genome of the psychrophilic Antarctic marine bacterium Pseudoalteromonas haloplanktis TAC125 (PhTAC125) is endowed with three genes encoding 2-on-2 haemoglobins. To investigate the function played by one of the three trHbs, PhHbO, a PhTAC125 genomic mutant strain was constructed, in which the encoding gene was knocked-out. The mutant strain was grown under controlled conditions and several aspects of bacterium physiology were compared with those of wild-type cells when dissolved oxygen pressure in solution and growth temperature were changed. Interestingly, inactivation of the PhHbO encoding gene makes the mutant bacterial strain sensitive to high solution oxygen pressure, to H(2)O(2), and to a nitrosating agent, suggesting the involvement of PhHbO in oxidative and nitrosative stress resistance.
Parrilli
Ermenegilda
E
Dipartimento di Chimica Organica e Biochimica, Università di Napoli Federico II - Complesso Universitario M.S. Angelo, via Cinthia 4, 80126 Naples, Italy.
Giuliani
Maria
M
Giordano
Daniela
D
Russo
Roberta
R
Marino
Gennaro
G
Verde
Cinzia
C
Tutino
Maria Luisa
ML
D000595:Amino Acid Sequence; D000864:Antarctic Regions; D001483:Base Sequence; D017931:DNA Primers; D005798:Genes, Bacterial; D006454:Hemoglobins / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D015538:Nitrosation; D018384:Oxidative Stress; D031161:Pseudoalteromonas / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D006454:Hemoglobins