Title : Solution structure and sugar-binding mechanism of mouse latrophilin-1 RBL: a 7TM receptor-attached lectin-like domain
Abstract :
Latrophilin-1 ( Lat-1 ), a target receptor for alpha-Latrotoxin, is a putative G protein-coupled receptor implicated in synaptic function
The extracellular portion of Lat-1 contains a rhamnose binding lectin (RBL)-like domain of unknown structure
RBL domains , first isolated from the eggs of marine species, are also found in the ectodomains of other metazoan transmembrane proteins , including a recently discovered coreceptor of the neuronal axon guidance molecule SLT-1 /Slit
Here, we describe a structure of this domain from the mouse Lat-1
RBL adopts a unique alpha/beta fold with long structured loops important for monosaccharide recognition , as shown in the structure of a complex with L-rhamnose.
Sequence alignments and mutagenesis show that residues important for carbohydrate binding are often absent in other receptor-attached examples of RBL, including the SLT-1 /Slit coreceptor
We postulate that this domain class facilitates direct protein-protein interactions in many transmembrane receptors