A novel alpha-helix in the first fibronectin type III repeat of the neural cell adhesion molecule is critical for N-glycan polysialylation.

Polysialic acid is a developmentally regulated, anti-adhesive glycan that is added to the neural cell adhesion molecule, NCAM. Polysialylated NCAM is critical for brain development and plays roles in synaptic plasticity, axon guidance, and cell migration. The first fibronectin type III repeat of NCAM, FN1, is necessary for the polysialylation of N-glycans on the adjacent immunoglobulin domain.

Structural basis of antigen mimicry in a clinically relevant melanoma antigen system.

Although mimics of human tumor antigens are effective immunogens to overcome host unresponsiveness to the nominal antigen, the structural basis of this mimicry remains poorly defined. Therefore, in this study we have characterized the structural basis of the human high molecular weight-melanoma-associated antigen (HMW-MAA) mimicry by the mouse anti-idiotypic (anti-id) monoclonal antibody (mAb) MK2-23. Using x-ray crystallography, we have characterized the three-dimensional structure of the anti-id mAb MK2-23 Fab' and shown that its heavy chain complementarity-determining region (CDR3) (H3) and its light chain CDR1 (L1) are closely associated.

Structure of human estrone sulfatase suggests functional roles of membrane association.

Estrone sulfatase (ES; 562 amino acids), one of the key enzymes responsible for maintaining high levels of estrogens in breast tumor cells, is associated with the membrane of the endoplasmic reticulum (ER). The structure of ES, purified from the microsomal fraction of human placentas, has been determined at 2.60-A resolution by x-ray crystallography.