Plant Hemoglobins

Arredondo‐Peter, Raúl; Hargrove, Mark S.; Morán, José F.; Sarath, Gautam; Klucas, Robert V.

doi:10.1104/pp.118.4.1121

Cited by 104 publications

(108 citation statements)

References 31 publications

Supporting

Mentioning

105

Contrasting

Unclassified

Order By: Relevance

“…Rice Hb1 to 4 are hexacoordinate and apparently rice Hb5 and tHb are pentacoordinate. The O 2 -association rate constants for hexacoordinate rice Hb1 and 2, and possibly for rice Hb3 and 4, are similar to those of other O 2 -transport and -storage proteins, such as the spermwhale myoglobin and soybean Lb a 8, 16, 75, 97 . However, in rice Hb1 2 and 2 16 , and possibly in rice Hb3 and 4, the bound O 2 is stabilized by distal His after binding to the Fe-heme, which results in very low O 2 -dissociation rate constants.…”

Section: Structure and Biophysical Properties Of Rice Hemoglobinssupporting

confidence: 54%

See 1 more Smart Citation

Rice (Oryza) hemoglobins

2014

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Structure and Biophysical Properties Of Rice Hemoglobinssupporting

confidence: 54%

“…It was proposed that one of the functions of plant Hbs could be related to the peroxidase activity 8, 106 . This is of interest because peroxidase activity modulates the levels of reactive oxygen species and a variety of cellular processes 137– 143 .…”

Section: Postulated Functions For Rice Hemoglobinsmentioning

confidence: 99%

Rice (Oryza) hemoglobins

2014

Self Cite

View full text Add to dashboard Cite

show abstract

“…For example, the k′O 2 value for rice recombinant Hb1 is 316-fold lower than the k′O 2 of sperm whale myoglobin [4,5]. This observation suggests that nsHbs do not release O 2 after oxygenation, and that these proteins might not func-tion as O 2 -carriers.…”

Section: Introductionmentioning

confidence: 97%

“…NsHbs have been detected in a number of land plants, ranging from primitive bryophytes [6] to angiosperms [4,22]. The nshb genes are expressed in plant embryonic and vegetative organs, and upregulation of nshb genes occurs in plants that are subjected to energetic stress, such as microaerobiosis and light limitation [19,24,26].…”

Section: Introductionmentioning

confidence: 99%

“…This observation suggests that nsHbs do not release O 2 after oxygenation, and that these proteins might not func-tion as O 2 -carriers. However, it has been hypothesized that nsHbs interact with regulatory molecules in plants [4]. A possible consequence of such interactions might be a change in the nsHb tertiary structure and kinetic constants, perhaps allowing nsHbs to function as O 2 -carriers or as O 2 -donors.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Saenz-Rivera

Sarath

Arredondo‐Peter

2004

Plant Physiology and Biochemistry

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Legume Root Architecture: A Peculiar Root System

Gonzalez‐Rizzo

Laporte

Crespi

et al. 2018

Annual Plant Reviews Online

View full text Add to dashboard Cite

The soil environmental conditions and symbiotic interactions are the major determinants of legume root architecture. Investigating cues that affect root developmental adaptations to the environment as well as understanding the mechanisms underlying the control of the root architecture are crucial to improve agronomical traits, notably in the legume family. Indeed, legumes are one of the most widespread crops, in terms of number and diversity of cultivated species.Legume roots can develop two types of secondary root organs: lateral roots and nitrogen‐fixing nodules. Lateral root formation is common to all higher plants; however, nodules are present only on legume roots as a result of the symbiotic interaction with nitrogen‐fixing soil bacteria, collectively known as rhizobia. The only nonlegume plants described to be able to interact with rhizobia to form nitrogen‐fixing nodules areParasponiaspp.What makes the legume root system so peculiar? The aim of this chapter is to give an overview of the current knowledge of the development of secondary root organs in legumes. A comparative analysis of their structure and ontogeny will be presented, and the specific and common regulatory mechanisms involved will be described.

show abstract

Plant Hemoglobins

Cited by 104 publications

References 31 publications

Rice (Oryza) hemoglobins

Rice (Oryza) hemoglobins

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

Legume Root Architecture: A Peculiar Root System

Contact Info

Product

Resources

About