Mechanism of Ca2- and Monosaccharide Binding to a C-type Carbohydrate-recognition Domain of the Macrophage Mannose Receptor

Abstract

. Alanine-scanning mutagenesis was used to identify two other asparagine residues and one glutamic acid residue that are probably involved in ligation of the auxiliary Ca 2؉ to CRD-4. Sequence comparisons with other C-type CRDs suggest that the proposed binding site for the auxiliary Ca 2؉ in CRD-4 of the mannose receptor is unique. Evidence that the conserved Ca 2؉ in CRD-4 bridges between the protein and bound sugar in a manner analogous to MBP-A was obtained by mutation of one of the amino acid side chains at this site. Ring current shifts seen in the 1 H NMR spectra of methyl glycosides of mannose, GlcNAc, and fucose in the presence of CRD-4 and site-directed mutagenesis indicate that a stacking interaction with Tyr 729 is also involved in binding of sugars to CRD-4. This interaction contributes about 25% of the total free energy of binding to mannose. C-5 and C-6 of mannose interact with Tyr 729 , whereas C-2 of GlcNAc is closest to this residue, indicating that these two sugars bind to CRD-4 in opposite orientations. Sequence comparisons with other mannose/GlcNAc-specific C-type CRDs suggest that use of a stacking interaction in the binding of these sugars is probably unique to CRD-4 of the mannose receptor.

A C-type lectin fold gene from Japanese scallop Mizuhopecten yessoensis, involved with immunity and metamorphosis

“…Mannose (or similar sugars with the equatorial 3-OH and 4-OH) is preferred by "EPN", whereas galactose (or similar sugars with the axial 3-OH and equatorial 4-OH) is preferred by "QPD" (Weis et al, 1998;Sujatha and Balaji, 2004). In addition, the CRD of MyCLF also had two putative sites, "QDC" and "WDD", for calcium binding (Mullin et al, 1997;Gourdine et al, 2007) The structure of CRD and the dependence of calcium suggested that MyCLF is a typical C-type lectin.…”

The LIMP-2/SCARB2 Binding Motif on Acid β-Glucosidase

“…Such structures are present in some receptors for carbohydrates (i.e. the macrophage mannose receptor that contains multiple carbohydrate binding domains with differing affinities/specificities for mannosyloligosaccharides) (35,36). Also, the cation-independent mannose 6-phos- Ϫ/Ϫ fibroblasts following transient transfections of each of the specified WT or alanine-substituted GCases in the TDK region.…”

Molecular cloning and expression analysis of a C-type lectin in the rock bream, Oplegnathus fasciatus

“…For example, the mammalian mannose-binding protein (MBP) (Weis et al, 1992;Weis et al, 1991), macrophage mannose receptor (Mullin et al, 1997) and selectins (Graves et al, 1994) require calcium for their activity.…”