(03413) Molecular Characterization of a New Lectin from the Marine Alga Ulva pertusa

Sheng WANG#, Fu-Di
ZHONG#, Yong-Jiang ZHANG, Zu-Jian WU, Qi-Ying LIN, and Lian-Hui XIE*
( Key Laboratory of Pesticide and Biochemistry,Ministry of Education, Institute
of Plant Virology,
Fujian Agriculture and Forestry University, Fuzhou 350002, China )

Abstract A new lectin, named
UPL1, was purified from a green alga Ulva pertusa by an affinity chromatography
on the bovine-thyroglobulin-Sepharose 4B column. The molecular mass of the algal
lectin was about 23 kD by SDS-PAGE, and it specifically agglutinated rabbit
erythrocytes. The hemagglutinating activity for rabbit erythrocytes could be
inhibited by bovine thyroglobulin and N-acetyl-D-glucosamine.
The lectin UPL1 required divalent cations for maintenance of its biological
activity, and was heat-stable, and had higher activity within pH 6-8. The N-terminal
amino acid sequence of the purified lectin was determined (P83209) and a set
of degenerate primers were designed. The full-length cDNA of the lectin was
cloned by rapid amplification of cDNA ends (RACE) method (AY433960). Sequence
analysis of upl1 indicated it was 1084 bp long, and encoded a premature
protein of 203 amino acids. The N-terminal sequence of the mature UPL1 polypeptide
started at amino acid 54 of the deduced sequence from the cDNA, indicating 53
amino acids lost due to posttranslational modification. The primary structure
of the Ulva pertusa lectin did not show amino acid sequence similarity
with known plant and animal lectins. Hence, this protein may be the paradigm
of a novel lectin family.

Key words Ulva pertusa;
lectin; purification; cloning

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Received: October 21, 2003 Accepted: December 2, 2003
This work was supported by a grant from the Local Key Project of China in Fujian
Province (2000H004)
# Who contributed equally to this article
*Corresponding author: Tel, 86-591-3769704; Fax, 86-591-3769704; E-mail, [email protected]