Abstract
The binding of NGF (nerve growth factor) to the rat low affinity nerve growth factor receptor (p75NGFR) has been studied by site-directed mutagenesis of the receptor. Introduction of non-native N-glycosylation sites within the binding domain indicates that the second of the characteristic cysteine-rich repeats may be particularly important to NGF binding. Two mutants of the second repeat, S42N and S66N, are glycosylated and bind NGF at a drastically reduced level, while still maintaining a conformation recognized by the monoclonal antibody against p75, MC192. Alanine substitution at these sites does not affect NGF binding. Two other mutations that result in local structural changes in the second repeat also greatly decrease binding. One of these altered residues, Ser50, appears to play an essential structural role, since it cannot be replaced by Asn, Ala, or Thr without loss of both NGF binding and MC192 recognition on a Western. Glycosylation of selected sites in the other repeats has little effect on NGF binding or antibody recognition. The introduction of non-native N-glycosylation sites may provide a generally useful scanning technique for the study of protein-protein interactions.
Highlights
P75NGFR belongs to a family of cell surface proteins that share a common four-repeat cystine motif in the extracellular
It seems highly probable that the backbone structure of the two proteins will turn out to be very similar, the surfaces are expected to vary considerably
Antibodies-MC192 is a monoclonal antibody against rat p75NGFR [29]
Summary
P75NGFR belongs to a family of cell surface proteins that share a common four-repeat cystine motif in the extracellular. The costs of publication of this article were defrayed in part by the payment of page charges. The three-dimensional structure of the cysteine-rich domain is not known for p75, but the corresponding domain of the p55TNFR has been crystallized in complex with its ligand, TNFJ3, and the structure determined to 1.8 A resolution [16]. In p75NGFR, as in p55TNFR, the ligand binding site is fully contained within this cysteine-rich domain [17, 18]. Certain residues that have been shown to form critical hydrogen bonds between J3-strands in the p55 structure are conserved in the p75 structure. It seems highly probable that the backbone structure of the two proteins will turn out to be very similar, the surfaces are expected to vary considerably
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
