A novel sialic acid-specific lectin from Phaseolus coccineus seeds with potent antineoplastic and antifungal activities.
A novel lectin (PCL) with specificity towards sialic acid was purified from Phaseolus coccineus L. (P. multiflorus willd) seeds using ion exchange chromatography on CM and DEAE-Sepharose, and gel filtration on Sephacryl S-200 column. PCL was a homodimer consisting of 29,831.265 Da subunits as determined by gel filtration and MS. Also, PCL was a non-metalloprotein and its N-terminal 23-amino acid sequence, ATETSFSFQRLNLANLVLNKESS, was determined. Subsequently, MTT method, cell morphological analysis and LDH activity-based cytotoxicity assays demonstrated that PCL was highly cytotoxic to L929 cells and induced apoptosis in a dose-dependent manner. Using caspase inhibitors, a typical caspase-dependent pathway was confirmed. PCL also showed remarkable antifungal activity towards some plant pathogenic fungi. Furthermore, when sialic acid-specific activity was fully inhibited, cytotoxicity and antifungal activity were abruptly decreased, respectively, suggesting a significant correlation between sialic acid-specific site and its bi-functional bioactivities.
Chen
Jing
J
College of Life Sciences, State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610064, China.
Liu
Bo
B
Ji
Na
N
Zhou
Jing
J
Bian
He-jiao
HJ
Li
Chun-yang
CY
Chen
Fang
F
Bao
Jin-ku
JK