[Molecular cloning and analysis of a monocot mannose-binding agglutinin from Zephyranthes grandiflora (family Amaryllidaceae)].

The monocot mannose-binding lectin can inhibit HIV from infecting the target cells. The total RNA of Zephyranthes grandiflora was extracted and reversely transcribed into cDNA. Degenerate primers were designed based on the conserved regions of other monocot mannose-binding agglutinins by homology alignment. The 694bp full-length cDNA of Zephyranthes grandiflora agglutinin (ZGA) was cloned by RT-PCR, 3' and 5' RACE (rapid amplification of cDNA ends). The start codon and stop codon of ZGA were at 37-39bp and 529-531bp respectively. The NCBI Blast analysis result showed that ZGA gene encoded a protein precursor with signal peptide, mature protein and C-terminal cleavage sequence. The mature ZGA protein contained 106 amino acids residues and its molecular weight was 11.6KD. The percentages of identity of the deduced mature ZGA protein with those of Galanthus nivalis agglutinin, Narcissus hybrid cultivar agglutinin, Lycoris radiate agglutinin and Clivia miniata agglutinin were 71.8%, 81%, 81.8% and 84.5%, respectively. Blocks analysis revealed that ZGA had three functional domains and three mannose-binding boxes (QDNY).