title: Electrochemical potential of Microgramma vaccinifolia rhizome lectin.
abstract: This work reports the isolation of Microgramma vaccinifolia rhizome lectin (MvRL) and the determination of electrochemical potentials of MvRL in the presence of Ca²⁺, Mg²⁺ and human type O erythrocytes. MvRL showed the highest specific hemagglutinating activity with human type O erythrocytes and showed a single polypeptide band of 17 kDa on SDS-PAGE. MvRL hemagglutinating activity was neutralized after dialysis with EDTA, and addition of Ca²⁺ and Mg²⁺ restored the activity. Electrochemical potentials of MvRL in the presence of 100 mM Ca²⁺ (882 mV) and 60 mM Mg²⁺ (1051 mV) were higher (p<0.05) than in the presence of only 0.15 M NaCl (247 mV), indicating that the electrochemical system was sensitive to structural and physico-chemical changes promoted by these ions. MvRL potential did not change in the presence of type O erythrocytes. The electrochemical system was able to detect changes in electrochemical potentials of MvRL promoted by Ca²⁺ and Mg²⁺, even in a complex environment (human serum supplemented with 40 and 60mM of these ions). The study reveals that the stimulatory effect of Ca²⁺ and Mg²⁺ on hemagglutinating activity may be linked to conformational change and/or alterations in surface charge distribution of MvRL.
authors.affiliation: Departamento de Bioquímica, CCB, Universidade Federal de Pernambuco, Avenida Professor Moraes Rego s/n, 50670-420, Cidade Universitária, Recife, PE, Brazil.
authors.forename: Giselly Maria de Sá
authors.initials: GM
authors.lastname: Santana
authors.forename: Lidiane Pereira de
authors.initials: LP
authors.lastname: Albuquerque
authors.forename: Thiago Henrique
authors.initials: TH
authors.lastname: Napoleão
authors.forename: Sandra Rodrigues de
authors.initials: SR
authors.lastname: Souza
authors.forename: Luana Cassandra Breitenbach Barroso
authors.initials: LC
authors.lastname: Coelho
authors.forename: Patrícia Maria Guedes
authors.initials: PM
authors.lastname: Paiva
mesh_terms: D002118:Calcium; D004563:Electrochemistry / Q000379:methods*; D004912:Erythrocytes; D006384:Hemagglutination; D006801:Humans; D037102:Lectins / Q000737:chemistry* / Q000302:isolation & purification; D008274:Magnesium; D011487:Protein Conformation; D027343:Rhizome / Q000737:chemistry*
chemical_list: D037102:Lectins; D008274:Magnesium; D002118:Calcium