Altering hemoglobin levels changes energy status in maize cells under hypoxia

Sowa, Aleksander; Duff, Stephen M. G.; Guy, Phillip A.; Hill, Robert D.

doi:10.1073/pnas.95.17.10317

Cited by 154 publications

(152 citation statements)

References 23 publications

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“…In Arabidopsis the symbiotic-like ahb2 gene was expressed at low levels in rosette leaves and was induced by low temperatures, whereas the nonsymbiotic ahb1 gene was expressed in roots and rosette leaves and levels of expression increased under hypoxic conditions, suggesting that AHb1 is a stressrelated protein (Trevaskis et al, 1997), as has been well documented for barley Hb (Taylor et al, 1994;Hill, 1998). There is also some evidence that a signal transduction pathway involving calcium-dependent protein kinase(s) and protein phosphatase(s) may be involved in barley hb gene expression (R.D.…”

Section: Nonsymbiotic Hbs Are Expressed In Diverse Plant Tissuesmentioning

confidence: 80%

“…The other group of plant Hbs, nonsymbiotic Hbs, appear to be ancestral to the symbiotic Hbs, are more widespread in the plant kingdom, and generally display a high affinity for oxygen. Their function in plants is the subject of much current inquiry (Appleby, 1992;Andersson et al, 1996;Arredondo-Peter et al, 1997a;Trevaskis et al, 1997;Hill, 1998). Some aspects of plant nonsymbiotic Hb function, particularly that of barley, have been succinctly reviewed by Hill (1998).…”

Section: Symbiotic and Nonsymbiotic Plant Hbs Belong To A Large Familmentioning

confidence: 99%

“…Recombinantly produced Hbs are indistinguishable from their native counterparts (Arredondo-Peter et al, 1997b;Duff et al, 1997;Hargrove et al, 1997) and have permitted detailed studies on the biochemical and biophysical properties of plant Hbs. This allows the study of protein structurefunction relationships and the use of recombinant proteins to obtain antibodies that cross-react with the native Hbs in plant extracts (Duff et al, 1998).…”

Section: Potential Functions Of Nonsymbiotic Plant Hbs: Multiple Rolementioning

confidence: 99%

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Plant Hemoglobins

et al. 1998

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Section: Nonsymbiotic Hbs Are Expressed In Diverse Plant Tissuesmentioning

confidence: 80%

Section: Symbiotic and Nonsymbiotic Plant Hbs Belong To A Large Familmentioning

confidence: 99%

Section: Potential Functions Of Nonsymbiotic Plant Hbs: Multiple Rolementioning

confidence: 99%

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Plant Hemoglobins

et al. 1998

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“…Based on the studies on over- and under-expressing barley nsHb in maize cells, it was proposed that under hypoxic conditions barley nsHb is involved in the ATP metabolism, particularly in maintaining the energy status under O 2 -limiting conditions 136 . Immunolocalization data showed that rice Hbs are localized in differentiating cells (see subsection on Gene expression and localization of hemoglobins in rice organs ) 70 .…”

Section: Postulated Functions For Rice Hemoglobinsmentioning

confidence: 99%

Rice (Oryza) hemoglobins

2014

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Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice ( Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a single copy of the thb gene exist in Oryza sativa var. indica and O. sativa var. japonica, Hb transcripts coexist in rice organs and Hb polypeptides exist in rice embryonic and vegetative organs and in the cytoplasm of differentiating cells. At the structural level, the crystal structure of rice Hb1 has been elucidated, and the structures of the other rice Hbs have been modeled. Kinetic analysis indicated that rice Hb1 and 2, and possibly rice Hb3 and 4, exhibit an extremely high affinity for O 2, whereas rice Hb5 and tHb possibly exhibit a low to moderate affinity for O 2. Based on the accumulated information on the properties of rice Hbs and data from the analysis of other plant and non-plant Hbs, it is likely that Hbs play a variety of roles in rice organs, including O 2-transport, O 2-sensing, NO-scavenging and redox-signaling. From an evolutionary perspective, an outline for the evolution of rice Hbs is available. Rice nshb and thb genes vertically evolved through different lineages, rice nsHbs evolved into clade I and clade II lineages and rice nshbs and thbs evolved under the effect of neutral selection. This review also reveals lacunae in our ability to completely understand rice Hbs. Primary lacunae are the absence of experimental information about the precise functions of rice Hbs, the properties of modeled rice Hbs and the cis-elements and trans-acting factors that regulate the expression of rice hb genes, and the partial understanding of the evolution of rice Hbs.

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“…Although the function of nsHbs is still not known, recent work suggests that these proteins play important roles in plant metabolism. For example, it has been proposed that barley nsHb functions by modulating the energy status and NO-levels in transgenic maize cells [23] and stressed alfalfa root cultures [10], respectively.…”

Section: Introductionmentioning

confidence: 99%

Modeling the tertiary structure of a maize (Zea mays ssp. mays) non-symbiotic hemoglobin

Saenz-Rivera

Sarath

Arredondo‐Peter

2004

Plant Physiology and Biochemistry

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Modeling the tertiary structure of a maize (Zea mays ssp. mays) nonsymbiotic hemoglobin" (2004 AbstractThe tertiary structure of a maize (Zea mays ssp. mays) non-symbiotic hemoglobin (Hbm) was modeled using computer tools and the known tertiary structure of rice Hb1 as a template. This method was tested by predicting the tertiary structure of soybean leghemoglobin a (Lba) using rice Hb1 as a template. The tertiary structures of the predicted and native Lba were similar, indicating that our computer methods could reliably predict the tertiary structures of plant Hbs. We next predicted the tertiary structure of Hbm. Hbm appears to have a long pre-helix A and a large CD-loop. The positions of the distal and proximal His are identical in Hbm and rice Hb1, which suggests that heme-Fe is hexacoordinate in Hbm and that the kinetic properties of Hbm and rice Hb1 are expected to be very similar, i.e. that Hbm has a high O 2 -affinity. Thermostability analysis showed that Hbm CD-loop is unstable and may provide mobility to amino acids located at the heme pocket for both ligand binding and stabilization and heme-Fe coordination. Analysis of the C-terminal half of Hbm showed the existence of a pocket-like region (the N/C cavity) where interactions with organic molecules or proteins could be possible. Lys K94 protrudes into the N/C cavity, suggesting that K94 may sense the binding of molecules to the N/C cavity. Thus, it is likely that the instability of the CD-loop and the possibility of binding molecules to the N/C cavity are essential for positioning amino acids in the heme pocket and in regulating Hbm activity and function.

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Altering hemoglobin levels changes energy status in maize cells under hypoxia

Abstract: Nonsymbiotic hemoglobins are broadly present across the plant kingdom; however, the function of these proteins is unknown. Cultured

Cited by 154 publications

References 23 publications

Plant Hemoglobins

Plant Hemoglobins

Rice (Oryza) hemoglobins

Modeling the tertiary structure of a maize (Zea mays ssp. mays) non-symbiotic hemoglobin

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