title: Native crystal structure of a nitric oxide-releasing lectin from the seeds of Canavalia maritima.
abstract: Here, we report the crystallographic study of a lectin from Canavalia maritima seeds (ConM) and its relaxant activity on vascular smooth muscle, to provide new insights into the understanding of structure/function relationships of this class of proteins. ConM was crystallized and its structure determined by standard molecular replacement techniques. The amino acid residues, previously suggested incorrectly by manual sequencing, have now been determined as I17, I53, S129, S134, G144, S164, P165, S187, V190, S169, T196, and S202. Analysis of the structure indicated a dimer in the asymmetric unit, two metal binding sites per monomer, and loops involved in the molecular oligomerization. These confer 98% similarity between ConM and other previously described lectins, derived from Canavalia ensiformis and Canavalia brasiliensis. Our functional data indicate that ConM exerts a concentration-dependent relaxant action on isolated aortic rings that probably occurs via an interaction with a specific lectin-binding site on the endothelium, resulting in a release of nitric oxide.
authors.affiliation: BioMol-Lab/Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Brazil.
authors.forename: Carlos Alberto de Almeida
authors.initials: CA
authors.lastname: Gadelha
authors.forename: Frederico Bruno Mendes Batista
authors.initials: FB
authors.lastname: Moreno
authors.forename: Tatiane
authors.initials: T
authors.lastname: Santi-Gadelha
authors.forename: João Batista
authors.initials: JB
authors.lastname: Cajazeiras
authors.forename: Bruno Anderson Matias da
authors.initials: BA
authors.lastname: Rocha
authors.forename: Ana Maria Sampaio
authors.initials: AM
authors.lastname: Assreuy
authors.forename: Mário Rogério
authors.initials: MR
authors.lastname: Lima Mota
authors.forename: Nilson Vieira
authors.initials: NV
authors.lastname: Pinto
authors.forename: Ana Vaneska
authors.initials: AV
authors.lastname: Passos Meireles
authors.forename: Júlio César
authors.initials: JC
authors.lastname: Borges
authors.forename: Beatriz Tupinamba
authors.initials: BT
authors.lastname: Freitas
authors.forename: Fernanda
authors.initials: F
authors.lastname: Canduri
authors.forename: Emmanuel Prata
authors.initials: EP
authors.lastname: Souza
authors.forename: Plínio
authors.initials: P
authors.lastname: Delatorre
authors.forename: David Neil
authors.initials: DN
authors.lastname: Criddle
authors.forename: Walter Filgueira
authors.initials: WF
authors.lastname: de Azevedo
authors.forename: Benildo Sousa
authors.initials: BS
authors.lastname: Cavada
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology; D001665:Binding Sites; D032449:Canavalia / Q000737:chemistry* / Q000235:genetics; D003208:Concanavalin A / Q000235:genetics / Q000494:pharmacology; D018360:Crystallography, X-Ray; D004730:Endothelium, Vascular / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D010656:Phenylephrine / Q000494:pharmacology; D037121:Plant Lectins / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D051381:Rats; D017208:Rats, Wistar; D012639:Seeds / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity; D014664:Vasodilation / Q000187:drug effects
chemical_list: D004791:Enzyme Inhibitors; D037121:Plant Lectins; D003208:Concanavalin A; D010656:Phenylephrine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester