Maackia amurensis seed lectin structure and sequence comparison with other M. amurensis lectins

Maackia amurensis lectins, including MASL, MAA, and MAL2, are widely utilized in biochemical and medicinal research. However, the structural and functional differences between these lectins have not been defined. Here, we present a high-resolution cryo-EM structure of MASL revealing that its tetrame...

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Bibliographic Details
Published in:The Journal of biological chemistry Vol. 301; no. 5; p. 108466
Main Authors: Nayak, Ashok R., Holdcraft, Cayla J., Yin, Ariel C., Nicoletto, Rachel E., Zhao, Caifeng, Zheng, Haiyan, Temiakov, Dmitry, Goldberg, Gary S.
Format: Journal Article
Language:English
Published: United States Elsevier Inc 01.05.2025
American Society for Biochemistry and Molecular Biology
Subjects:
Amino Acid Sequence
cryo-EM
Cryoelectron Microscopy
lectin
Lectins - chemistry
Maackia amurensis
Maackia amurensis seed lectin
MASL
Plant Lectins - chemistry
Protein Multimerization
Seeds - chemistry
Maackia amurensis seed lectin
CTF
cryo-EM
lectin
Maackia amurensis
MASL
ISSN:0021-9258, 1083-351X
Online Access:Get full text
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Summary:Maackia amurensis lectins, including MASL, MAA, and MAL2, are widely utilized in biochemical and medicinal research. However, the structural and functional differences between these lectins have not been defined. Here, we present a high-resolution cryo-EM structure of MASL revealing that its tetrameric assembly is directed by two intersubunit disulfide bridges. These bridges, formed by C272 residues, are central to the dimer-of-dimers assembly of a MASL tetramer. This cryo-EM structure also identifies residues involved in stabilizing the dimer interface, multiple glycosylation sites, and calcium and manganese atoms in the sugar-binding pockets of MASL. Notably, our analysis reveals that Y250 in the carbohydrate-binding site of MASL adopts a flipped conformation, likely acting as a gatekeeper that obstructs access to noncognate substrates, a feature that may contribute to MASL’s substrate specificity. Sequence analysis suggests that MAA is a truncated version of MASL, while MAL2 represents a homologous isoform. Unlike MASL, neither MAL2 nor MAA contains a cysteine residue required for disulfide bridge formation. Accordingly, analysis of these proteins using reducing and nonreducing SDS-PAGE confirms that the C272 residue in MASL drives intermolecular disulfide bridge formation. These findings provide critical insights into the unique structural features of MASL that distinguish it from other M. amurensis lectins, offering a foundation for further exploration of its biological and therapeutic potential.
Bibliography:These authors contributed equally to this work.
ISSN:0021-9258
1083-351X
DOI:10.1016/j.jbc.2025.108466