Nitric oxide heme interactions in nitrophorin from Cimex lectularius

• Published in: Hyperfine interactions Vol. 237; no. 1; pp. 1 - 5
• Main Authors: Christmann, R., Auerbach, H., Berry, R. E., Walker, F. A., Schünemann, V.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.12.2016; Springer Nature B.V
• Subjects: 13-18 September 2015; Atomic; Blood coagulation; Condensed Matter Physics; Density functional theory; Germany; Hadrons; Hamburg; Heavy Ions; Insects; Iron; Iron 57; Molecular; Mossbauer spectroscopy; Nitric oxide; Nuclear Physics; Optical and Plasma Physics; Physics; Physics and Astronomy; Proceedings of the International Conference on the Applications of the Mössbauer Effect (ICAME 2015); Salivary glands; Surfaces and Interfaces; Thin Films; Vasodilation; Nitrophorin; Density functional theory; Nitric oxide; Mössbauer spectroscopy; Heme
• ISSN: 0304-3843; 1572-9540
• DOI: 10.1007/s10751-016-1240-6

The nitrophorin from the bedbug Cimex lectularius (cNP) is a nitric oxide (NO) carrying protein. Like the nitrophorins (rNPs) from the kissing bug Rhodnius prolixus, cNP forms a stable heme Fe(III)-NO complex, where the NO can be stored reversibly for a long period of time. In both cases, the NPs are found in the salivary glands of blood-sucking bugs. The insects use the nitrophorins to transport the NO to the victim’s tissues, resulting in vasodilation and reduced blood coagulation. However, the structure of cNP is significantly different to those of the rNPs from Rhodnius prolixus . Furthermore, the cNP can bind a second NO molecule to the proximal heme cysteine when present at higher concentrations. High field Mössbauer spectroscopy on 57 Fe enriched cNP complexed with NO shows reduction of the heme iron and formation of a ferrous nitric oxide (Fe(II)-NO) complex. Density functional theory calculations reproduce the experimental Mössbauer parameters and confirm this observation.