Background Nitrogen is an essential nutrient in plant growth. The ability of a plant to supply
all or part of its requirements from biological nitrogen fixation (BNF) thanks to interactions …

Nitrite is one of the players in the broad nitrogen biogeochemical cycle. This nitrogen oxo-
anion is involved in key pathways crucial to life on Earth and to the planetary “recycling” of …

Background and aims After a series of seminal works during the last decade of the 20th
century, nitric oxide (NO) is now firmly placed in the pantheon of plant signals. Nitric oxide …

Hemoglobins are ubiquitous in nature and among the best-characterized proteins [1–9].
Genetics has revealed crucial roles for human hemoglobins [10], but similar data are lacking …

Agrobacterium is widely considered to be the only bacterial genus capable of transferring
genes to plants. When suitably modified, Agrobacterium has become the most effective …

Nitric oxide (NO) is a widespread signaling molecule, and numerous targets of its action
exist in plants. Whereas the activity of NO in erythrocytes, microorganisms, and invertebrates …

Horizontal gene transfer (HGT) has played a major role in bacterial evolution and is fairly
common in certain unicellular eukaryotes. However, the prevalence and importance of HGT …

Truncated hemoglobins (trHbs) 1 (1) constitute a family of small oxygen-binding heme
proteins distributed in eubacteria, cyanobacteria, protozoa, and plants (Table I …

Amino acid composition of proteins varies substantially between taxa and, thus, can evolve.
For example, proteins from organisms with (G+ C)-rich (or (A+ T)-rich) genomes contain …

Neuroglobin and cytoglobin reversibly bind oxygen in competition with the distal histidine,
and the observed oxygen affinity therefore depends on the properties of both ligands. In the …