Comparative kinetic analysis of anaerobic nitrite metabolism in phytoglobins

dc.contributor.advisor Mark S. Hargrove Spooner, Ashley
dc.contributor.department Biochemistry, Biophysics and Molecular Biology 2018-08-11T12:21:09.000 2020-06-30T03:08:08Z 2020-06-30T03:08:08Z Fri Jan 01 00:00:00 UTC 2016 2001-01-01 2016-01-01
dc.description.abstract <p>During the course of a plant’s life cycle, there are times when oxygen is a finite resource such as in rapidly growing and metabolizing tissue, in flooding, or in waterlogged root systems. When this occurs the plant develops alternative means of respiration for survival in order to cope with this hypoxic stress. The hypoxic plant cell will use nitrate and nitrite as alternative terminal electron acceptors. Increasing levels of nitrite during hypoxia are connected to higher NO levels within plants. However, in plants overexpressing Hbs there is decreased NO emission. Previous studies have confirmed that the Class 1 phytoglobin, Rice nonsymbiotic hemoglobin (nsHb) 1, could convert nitrite to NO (1). Earlier experiments have also shown the correlation between oxygen affinity and phytoglobin class (2), as well as the ability of hemoglobins to perform the NO dioxygenase reaction in hypoxic environments (3, 4). In fact, plants over-expressing class 1 phytoglobins during hypoxia released less NO (3), and had higher metabolic activity (5) as compared to WT plants. Taken all together, the nitrite reduction reaction presented a promising connection between NO detoxification and maintaining redox balance within the plant cell. This thesis project set out to investigate the relationship, if any, between phytoglobin class and nitrite reduction to NO. To further understand and delineate the functions of the distinct classes of phytoglobins, a comparative kinetic analysis of nitrite reduction across classes was performed. Overall, the capacity of phytoglobins to reduce nitrite to NO appears to cluster according to phytoglobin class, with class 1 being consistently high performers as compared to animal hemoglobins, and the recently evolved symbiotic and leghemoglobin classes being the least efficient at nitrite reduction.</p>
dc.format.mimetype application/pdf
dc.identifier archive/
dc.identifier.articleid 7026
dc.identifier.contextkey 11169554
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath etd/16019
dc.language.iso en
dc.source.bitstream archive/|||Fri Jan 14 20:53:58 UTC 2022
dc.subject.disciplines Biochemistry
dc.subject.keywords Hb/NO cycle
dc.subject.keywords hemoglobin
dc.subject.keywords Nitric oxide
dc.subject.keywords nitrite reduction
dc.subject.keywords phytoglobin
dc.subject.keywords plant hypoxia
dc.title Comparative kinetic analysis of anaerobic nitrite metabolism in phytoglobins
dc.type article
dc.type.genre thesis
dspace.entity.type Publication
relation.isOrgUnitOfPublication faf0a6cb-16ca-421c-8f48-9fbbd7bc3747 Biochemistry thesis Master of Science
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