The effects of bound anions on the reactivity of residues in hemerythrin

Ligands of boron in Pisum sativum nodules are involved in regulation of oxygen concentration and rhizobial infection

“…Lb is a non-glycosylated protein, but borate is able to interact with aminoacyl residues such as hydroxyl groups of serine or threonine, or amine groups of arginine, as described for the bacterial quorum sensor AI2 (Chen et al 2002) and likely for the boronic acid-mediated inhibition of serine proteases (Kettner & Shenvi 1984). Additionally, it was also reported that B forms covalent bonds with amine groups near the coordination Fe site of the oxygen carrier hemerythrin of Golfingia gouldii (Garbett, Darnall & Klotz 1971). Therefore, it would be interesting to test the possibility of covalent binding of B with Lb and other heme oxygen carriers, and whether this could have a physiological importance.…”

Boron Functions in Plants and Animals: Recent Advances in Boron Research and Open Questions

“…Boron is able to form covalent bonds with the nitrogen atom of amine groups, e.g. in hemerythrin (a nonheme iron-containing oxygen transport protein of Golfingia gouldii), where it binds near the coordination iron site (Garbett et al 1971). Whether the stability of this type of boron complex is high enough and comparable to polyols to be of biological relevance remains to be shown.…”

Boron in the Environment

“…20, 21 Sah and Brown 22 have made a comprehensive review of published methods of sample preparation, determinant purification, and determination of B in samples. Among nuclear techniques, 11 B-NMR seems to be a powerful tool, not only for detecting borate cross-linked biomolecules, but also for analyzing the type of borate complex. Although most spectrophotometric methods are based on colorimetric reactions of oxy-B complexes with azomethine-H, curcumin, or carmine, other colorimetric and fluorometric methods have also been used to some extent.…”