The CI-MPR and CD-MPR are able to bind to this wide range of N-glycan structures by having a different binding site architecture. The MPRs also bind to the phosphate group in a slightly different manner. Domain 3 of the CI-MPR uses Ser-386 and an ordered water molecule to bind to the phosphate moiety. On the other hand, the CD-MPR uses residues Asp-103, Asn-104 and His-105 to form favourable hydrogen bonds to the phosphate group. The CD-MPR also contains a divalent cation Mn2+ which forms favourable hydrogen bonds with the phosphate moiety.
