Conformation and activity ofPhaseolus coccineus var. rubronanus lectin

Abstract

The conformation of native and denatured Phaseolus coccineus var. rubronanus lectin was studied by circular dichroism (CD) and correlated to the hemagglutinating activity. The far-UV CD spectrum at 25 degrees C showed a broad, negative band around 223 nm and a positive one at 196 nm. CD data analysis of the lectin indicated a beta-sheet-rich protein. At high temperatures, the spectrum was blue-shifted with increasing magnitude; these changes correlated well with the loss of the activity. The conformation of lectin between pH 2 and 10 remained essentially unchanged. At pH 13 the CD spectrum resembled that of unordered form with a negative band near 200 nm and the activity was completely lost. The denatured lectin in 6 M guanidine hydrochloride would be renatured upon diluting the denaturant to 0.75 M; the changes in CD spectrum again correlated well with the loss of the activity. The effect of sodium dodecyl sulfate on the lectin was drastic; it sharply increased the alpha-helix at the expense of the beta-sheet and reduced the activity; the changes reached a plateau above 20 mM surfactant.

Erythroagglutinin fromPhaseolus coccineusVar. Alubia: Chemical Characterization, Sugar Specificity, and Effect on Blood Coagulation Factors

“…Other vari-eties are constituted by three, two, or one lectin subunit, and their biological activity is well correlated with the type of subunit present in such varieties (Brown et al, 1982;Leavitt et al, 1977). Interestingly, reports concerning lectins from P. coccineus indicated that all of them are composed by four identical subunits and show mitogenic and erythroagglutinating activities (Nowakova and Kocourek, 1974;Shi et al, 1993;Feria et al, 1996). As we show in this work P. coccineus var.…”

“…P. coccineus var. Rubronanus (Shi et al, 1993) and P. coccineus var. Alubia lectins (Ochoa and Kristiansen, 1982) are not blood group specific; Alubia lectin was shown to have mitogenic and immunosuppressive activities (Calderon and Cordoba, 1976).…”

Binding Specificity ofPhilyra pisumLectin to Pathogen-Associated Molecular Patterns, and Its Secondary Structure

“…In contrast, the PAMP-binding domain of PRP obtained from the hemolymph of a pyralid moth reportedly consists primarily of α-helix, with only a small amount of β-sheet [30]. PPL contains a relatively low proportion of α-helix, which is broadly consistent with reports for legume lectins (as also determined using the protocol of Yang et al) including a low proportion (less than 30%) of α-helix and a high proportion (more than 60%) of β-sheet [11,31,32]. …”

Bioactive Compounds of Runner Bean (Phaseolus coccineus L.)

“…A tetrameric lectin of 112 kDa consisting of four similar subunits (28 kDa) containing 20% w/w of glucosamine was purified from the seeds of "alubia," a Mexican strain of P. coccineus [43]. A lectin (128 kDa) with four identical subunits has been isolated and characterized from a variant of scarlet runner bean [44]. A tetrameric anti-A1 lectin with a molecular weight of 120 kDa was isolated from the edible bean of P. coccineus from Oaxaca, Mexico [45].…”