Functional and structural characterization of the 2/2 Hemoglobin from Synechococcus sp. PCC 7002

Nancy L. Scott, Yu Xu, Gaozhong Shen, David A. Vuletich, Christopher J. Falzone, Zhongkui Li, Marcus Ludwig, Matthew P. Pond, Matthew R. Preimesberger, Donald Ashley Bryant, Juliette T.J. Lecomte

Research output: Contribution to journalArticle

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Abstract

Cyanobacterium Synechococcus sp. PCC 7002 contains a single gene (glbN) coding for GlbN, a protein of the 2/2 hemoglobin lineage. The precise function of GlbN is not known, but comparison to similar 2/2 hemoglobins suggests that reversible dioxygen binding is not its main activity. In this report, the results of in vitro and in vivo experiments probing the role of GlbN are presented. Transcription profiling indicated that glbN is not strongly regulated under any of a large number of growth conditions and that the gene is probably constitutively expressed. High levels of nitrate, used as the sole source of nitrogen, and exposure to nitric oxide were tolerated better by the wild-type strain than a glbN null mutant, whereas overproduction of GlbN in the null mutant background restored the wild-type growth. The cellular contents of reactive oxygen/nitrogen species were elevated in the null mutant under all conditions and were highest under NO challenge or in the presence of high nitrate concentrations. GlbN overproduction attenuated these contents significantly under the latter conditions. The analysis of cell extracts revealed that the heme of GlbN was covalently bound to overproduced GlbN apoprotein in cells grown under microoxic conditions. A peroxidase assay showed that purified GlbN does not possess significant hydrogen peroxidase activity. It was concluded that GlbN protects cells from reactive nitrogen species that could be encountered naturally during growth on nitrate or under denitrifying conditions. The solution structure of covalently modified GlbN was determined and used to rationalize some of its chemical properties.

Original languageEnglish (US)
Pages (from-to)7000-7011
Number of pages12
JournalBiochemistry
Volume49
Issue number33
DOIs
StatePublished - Aug 24 2010

Fingerprint

Synechococcus
Nitrates
Reactive Nitrogen Species
Hemoglobins
Peroxidase
Nitrogen
Growth
Genes
Oxygen
Apoproteins
Cyanobacteria
Transcription
Cell Extracts
Heme
Chemical properties
Hydrogen
Assays
Reactive Oxygen Species
Nitric Oxide
Cells

All Science Journal Classification (ASJC) codes

  • Biochemistry

Cite this

Scott, N. L., Xu, Y., Shen, G., Vuletich, D. A., Falzone, C. J., Li, Z., ... Lecomte, J. T. J. (2010). Functional and structural characterization of the 2/2 Hemoglobin from Synechococcus sp. PCC 7002. Biochemistry, 49(33), 7000-7011. https://doi.org/10.1021/bi100463d
Scott, Nancy L. ; Xu, Yu ; Shen, Gaozhong ; Vuletich, David A. ; Falzone, Christopher J. ; Li, Zhongkui ; Ludwig, Marcus ; Pond, Matthew P. ; Preimesberger, Matthew R. ; Bryant, Donald Ashley ; Lecomte, Juliette T.J. / Functional and structural characterization of the 2/2 Hemoglobin from Synechococcus sp. PCC 7002. In: Biochemistry. 2010 ; Vol. 49, No. 33. pp. 7000-7011.
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abstract = "Cyanobacterium Synechococcus sp. PCC 7002 contains a single gene (glbN) coding for GlbN, a protein of the 2/2 hemoglobin lineage. The precise function of GlbN is not known, but comparison to similar 2/2 hemoglobins suggests that reversible dioxygen binding is not its main activity. In this report, the results of in vitro and in vivo experiments probing the role of GlbN are presented. Transcription profiling indicated that glbN is not strongly regulated under any of a large number of growth conditions and that the gene is probably constitutively expressed. High levels of nitrate, used as the sole source of nitrogen, and exposure to nitric oxide were tolerated better by the wild-type strain than a glbN null mutant, whereas overproduction of GlbN in the null mutant background restored the wild-type growth. The cellular contents of reactive oxygen/nitrogen species were elevated in the null mutant under all conditions and were highest under NO challenge or in the presence of high nitrate concentrations. GlbN overproduction attenuated these contents significantly under the latter conditions. The analysis of cell extracts revealed that the heme of GlbN was covalently bound to overproduced GlbN apoprotein in cells grown under microoxic conditions. A peroxidase assay showed that purified GlbN does not possess significant hydrogen peroxidase activity. It was concluded that GlbN protects cells from reactive nitrogen species that could be encountered naturally during growth on nitrate or under denitrifying conditions. The solution structure of covalently modified GlbN was determined and used to rationalize some of its chemical properties.",
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Scott, NL, Xu, Y, Shen, G, Vuletich, DA, Falzone, CJ, Li, Z, Ludwig, M, Pond, MP, Preimesberger, MR, Bryant, DA & Lecomte, JTJ 2010, 'Functional and structural characterization of the 2/2 Hemoglobin from Synechococcus sp. PCC 7002', Biochemistry, vol. 49, no. 33, pp. 7000-7011. https://doi.org/10.1021/bi100463d

Functional and structural characterization of the 2/2 Hemoglobin from Synechococcus sp. PCC 7002. / Scott, Nancy L.; Xu, Yu; Shen, Gaozhong; Vuletich, David A.; Falzone, Christopher J.; Li, Zhongkui; Ludwig, Marcus; Pond, Matthew P.; Preimesberger, Matthew R.; Bryant, Donald Ashley; Lecomte, Juliette T.J.

In: Biochemistry, Vol. 49, No. 33, 24.08.2010, p. 7000-7011.

Research output: Contribution to journalArticle

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T1 - Functional and structural characterization of the 2/2 Hemoglobin from Synechococcus sp. PCC 7002

AU - Scott, Nancy L.

AU - Xu, Yu

AU - Shen, Gaozhong

AU - Vuletich, David A.

AU - Falzone, Christopher J.

AU - Li, Zhongkui

AU - Ludwig, Marcus

AU - Pond, Matthew P.

AU - Preimesberger, Matthew R.

AU - Bryant, Donald Ashley

AU - Lecomte, Juliette T.J.

PY - 2010/8/24

Y1 - 2010/8/24

N2 - Cyanobacterium Synechococcus sp. PCC 7002 contains a single gene (glbN) coding for GlbN, a protein of the 2/2 hemoglobin lineage. The precise function of GlbN is not known, but comparison to similar 2/2 hemoglobins suggests that reversible dioxygen binding is not its main activity. In this report, the results of in vitro and in vivo experiments probing the role of GlbN are presented. Transcription profiling indicated that glbN is not strongly regulated under any of a large number of growth conditions and that the gene is probably constitutively expressed. High levels of nitrate, used as the sole source of nitrogen, and exposure to nitric oxide were tolerated better by the wild-type strain than a glbN null mutant, whereas overproduction of GlbN in the null mutant background restored the wild-type growth. The cellular contents of reactive oxygen/nitrogen species were elevated in the null mutant under all conditions and were highest under NO challenge or in the presence of high nitrate concentrations. GlbN overproduction attenuated these contents significantly under the latter conditions. The analysis of cell extracts revealed that the heme of GlbN was covalently bound to overproduced GlbN apoprotein in cells grown under microoxic conditions. A peroxidase assay showed that purified GlbN does not possess significant hydrogen peroxidase activity. It was concluded that GlbN protects cells from reactive nitrogen species that could be encountered naturally during growth on nitrate or under denitrifying conditions. The solution structure of covalently modified GlbN was determined and used to rationalize some of its chemical properties.

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