Native crystal structure of a nitric oxide-releasing lectin from the seeds of Canavalia maritima.
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.
Gadelha
Carlos Alberto de Almeida
CA
BioMol-Lab/Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Brazil.
Moreno
Frederico Bruno Mendes Batista
FB
Santi-Gadelha
Tatiane
T
Cajazeiras
João Batista
JB
Rocha
Bruno Anderson Matias da
BA
Assreuy
Ana Maria Sampaio
AM
Lima Mota
Mário Rogério
MR
Pinto
Nilson Vieira
NV
Passos Meireles
Ana Vaneska
AV
Borges
Júlio César
JC
Freitas
Beatriz Tupinamba
BT
Canduri
Fernanda
F
Souza
Emmanuel Prata
EP
Delatorre
Plínio
P
Criddle
David Neil
DN
de Azevedo
Walter Filgueira
WF
Cavada
Benildo Sousa
BS
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
D004791:Enzyme Inhibitors; D037121:Plant Lectins; D003208:Concanavalin A; D010656:Phenylephrine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester