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2018-07-18

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cc-by (c) Abbruzzetti, Stefania et al., 2018
Si us plau utilitzeu sempre aquest identificador per citar o enllaçar aquest document: https://hdl.handle.net/2445/128165

Electrostatic tuning of the ligand binding mechanism by Glu27 in nitrophorin 7

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Recurs relacionat

https://doi.org/10.1038/s41598-018-29182-3

Resum

Nitrophorins (NP) 1-7 are NO-carrying heme proteins found in the saliva of the blood-sucking insect Rhodnius prolixus. The isoform NP7 displays peculiar properties, such as an abnormally high isoelectric point, the ability to bind negatively charged membranes, and a strong pH sensitivity of NO afnity. A unique trait of NP7 is the presence of Glu in position 27, which is occupied by Val in other NPs. Glu27 appears to be important for tuning the heme properties, but its infuence on the pH-dependent NO release mechanism, which is assisted by a conformational change in the AB loop, remains unexplored. Here, in order to gain insight into the functional role of Glu27, we examine the efect of Glu27 → Val and Glu27 → Gln mutations on the ligand binding kinetics using CO as a model. The results reveal that annihilation of the negative charge of Glu27 upon mutation reduces the pH sensitivity of the ligand binding rate, a process that in turn depends on the ionization of Asp32. We propose that Glu27 exerts a through-space electrostatic action on Asp32, which shifts the pKa of the latter amino acid towards more acidic values thus reducing the pH sensitivity of the transition between open and closed states.

Matèries

Zoologia, Parasitologia, Biologia molecular, Receptors cel·lulars, Insectes hematòfags, Sang

Matèries (anglès)

Zoology, Parasitology, Molecular biology, Cell receptors, Bloodsucking insects, Blood

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Articles publicats en revistes (Nutrició, Ciències de l'Alimentació i Gastronomia)
<b>Publicacions de projectes de recerca finançats per la UE</b>
Articles publicats en revistes (Institut de Biomedicina (IBUB))

Citació

ABBRUZZETTI, Stefania, ALLEGRI, Alessandro, BIDON-CHANAL BADIA, Axel, OGATA, Hideaki, SOAVI, Giancarlo, CERULLO, Giulio, BRUNO, Stefano, MONTALI, Chiara, LUQUE GARRIGA, F. xavier, VIAPPIANI, Cristiano. Electrostatic tuning of the ligand binding mechanism by Glu27 in nitrophorin 7. _Scientific Reports_. 2018. Vol. 8, núm. 10855. [consulta: 20 de febrer de 2026]. ISSN: 2045-2322. [Disponible a: https://hdl.handle.net/2445/128165]

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