2r9k
From Proteopedia
Crystal Structure of Misteltoe Lectin I in Complex with Phloretamide
Structural highlights
Function[ML1_VISAL] The A chain is responsible for inhibiting protein synthesis through the catalytic inactivation of 60S ribosomal subunits by removing adenine from position 4,324 of 28S rRNA. The B chain binds to cell receptors and probably facilitates the entry into the cell of the A chain; B chains are also responsible for cell agglutination (lectin activity). Inhibits growth of the human tumor cell line Molt4.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe X-ray structure at 2.7A resolution of the complex between the European mistletoe lectin I (Viscum album, ML-I) and the plant growth hormone, 3-(p-hydroxyphenyl)-propionic acid amide (phloretamide, PA) from xylem sap has revealed the binding of PA at the so far undescribed hydrophobic cavity located between the two subunits of this ribosome-inhibiting protein. No such cavity is observed in related lectins. The binding of PA is achieved through interactions with the non-conserved residues Val228A, Leu230A, Arg388B, and the C-terminal Pro510B. It is conceivable that binding of PA to ML-I is part of a defence mechanism of the parasite against the host, whereby the parasite prevents the growth hormone of the host from interfering with its own regulatory system. The specific binding of PA to ML-I indicates that heterodimeric RIPs are multifunctional proteins whose functions in the cell have not yet been fully recognized and analyzed. The mistletoe lectin I--phloretamide structure reveals a new function of plant lectins.,Meyer A, Rypniewski W, Celewicz L, Erdmann VA, Voelter W, Singh TP, Genov N, Barciszewski J, Betzel Ch Biochem Biophys Res Commun. 2007 Dec 14;364(2):195-200. Epub 2007 Oct 5. PMID:17937929[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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