RRC ID 36035
Author Kiyokawa E, Makino A, Ishii K, Otsuka N, Yamaji-Hasegawa A, Kobayashi T.
Title Recognition of sphingomyelin by lysenin and lysenin-related proteins.
Journal Biochemistry
Abstract Lysenin is a sphingomyelin (SM)-specific toxin isolated from the coelomic fluid of the earthworm Eisenia foetida. Lysenin comprises a family of proteins together with lysenin-related protein 1 (LRP-1, lysenin 2) and LRP-2 (lysenin 3). In the present study, we characterized LRP-1 and LRP-2 together with lysenin using maltose-binding-protein-tagged recombinant proteins. LRP-2 specifically bound SM and induced hemolysis like lysenin. In contrast the binding and hemolytic activities of LRP-1 were 10 times less than those of lysenin and LRP-2. Lysenin and LRP-2 share 30 common sites of aromatic amino acids. Among them, only one position, phenylalanine 210, is substituted for isoleucine in LRP-1. The activity of LRP-1 was dramatically increased by introducing a single amino acid substitution of isoleucine 210 to phenylalanine, suggesting the importance of this aromatic amino acid in biological activities of lysenin and LRPs. The importance of aromatic amino acids was further indicated by a systematic tryptophan to alanine mutation of lysenin. Lysenin contains six tryptophan residues of which five are conserved in LRP-1 and -2. We showed that the conserved tryptophans but not the nonconserved one were required both in the recognition of SM and in the hemolytic activity of lysenin. Our results suggest the importance of tryptophan in the toxin function likely due to a direct recognition of SM or in maintaining the protein structure.
Volume 43(30)
Pages 9766-73
Published 2004-8-3
DOI 10.1021/bi049561j
PMID 15274631
MeSH Amino Acid Sequence Amino Acid Substitution / genetics Animals Carrier Proteins / chemistry Cell Line, Tumor Cells, Cultured Cytotoxins / chemistry Cytotoxins / genetics Cytotoxins / metabolism Hemolysis / genetics Humans Isoleucine / genetics Maltose-Binding Proteins Mice Molecular Sequence Data Oligochaeta* Phenylalanine / genetics Protein Binding / genetics Proteins / chemistry* Proteins / genetics Proteins / metabolism* Recombinant Proteins / chemistry Recombinant Proteins / genetics Recombinant Proteins / metabolism Sphingomyelins / chemistry Sphingomyelins / metabolism* Structural Homology, Protein* Toxins, Biological Tryptophan / chemistry Tryptophan / genetics
IF 2.952
Times Cited 50
DNA material pMAL/MBP-lysenin (RDB13958)