Publication
Title
A globin domain in a neuronal transmembrane receptor of **Caenorhabditis elegans** and **Ascaris suum** : molecular modeling and functional properties
Author
Abstract
We report the structural and biochemical characterization of GLB-33, a putative neuropeptide receptor that is exclusively expressed in the nervous system of the nematode Caenorhabditis elegans. This unique chimeric protein is composed of a 7 transmembrane domain, GLB-33 7TM, typical of a G-protein-coupled receptor, and of a globin domain, GLB-33 GD. Comprehensive sequence similarity searches in the genome of the parasitic nematode, Ascaris suum, revealed a chimeric protein that is similar to a Phe-Met-Arg-Phe-amide neuropeptide receptor. The three-dimensional structures of the separate domains of both species, and of the full-length proteins were modeled. The 7TM domains of both proteins appeared very similar, but the globin domain of the A. suum receptor surprisingly seemed to lack several helices, suggesting a novel truncated globin fold. The globin domain of C. elegans GLB-33, however, was very similar to a genuine myoglobin-type molecule. Spectroscopic analysis of the recombinant GLB-33 globin domain showed that the heme is pentacoordinate when ferrous and in the hydroxide-ligated form when ferric, even at neutral pH. Flash-photolysis experiments showed overall fast biphasic CO rebinding kinetics. In its ferrous deoxy form, GLB-33 GD is capable of reversibly binding O2 with a very high affinity and of reducing nitrite to nitric oxide faster than other globins. Collectively, these properties suggest that the globin domain of GLB-33 may serve as a highly sensitive oxygen-sensor and/or as a nitrite reductase. Both properties are potentially able to modulate the neuropeptide sensitivity of the neuronal transmembrane receptor.
Language
English
Source (journal)
Journal of biological chemistry. - Baltimore, Md
Publication
Baltimore, Md : 2015
ISSN
0021-9258
Volume/pages
290:16(2015), p. 10336-10352
ISI
000353241100036
Full text (Publisher's DOI)
Full text (open access)
Full text (publisher's version - intranet only)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identification
Creation 02.04.2015
Last edited 13.08.2017
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