High-resolution epitope mapping of hGH-receptor interactions by alanine-scanning mutagenesis.


A strategy, called alanine-scanning mutagenesis, was used to identify specific side chains in human growth hormone (hGH) that strongly modulate binding to the hGH receptor cloned from human liver. Single alanine mutations (62 in total) were introduced at every residue contained within the three discontinuous segments of hGH (residues 2 to 19, 54 to 74, and 167 to 191) that have been implicated in receptor recognition. The alanine scan revealed a cluster of a dozen large side chains that when mutated to alanine each showed more than a four times lower binding affinity to the hGH receptor. Many of these residues that promote binding to the hGH receptor are altered in homologs of hGH (such as placental lactogens and prolactins) that do not bind tightly to the hGH receptor. The overall folding of these mutant proteins was indistinguishable from that of the wild-type hGH, as determined by strong cross-reactivities with seven different conformationally sensitive monoclonal antibodies. The alanine scan also identified at least one side chain, Glu174, that hindered binding because when it was mutated to alanine the receptor affinity increased by more than a factor of four.

Submission Details

ID: q5qYddfW3

Submitter: Shu-Ching Ou

Submission Date: Aug. 14, 2018, 1:03 p.m.

Version: 1

Publication Details
Cunningham BC;Wells JA,Science (1989) High-resolution epitope mapping of hGH-receptor interactions by alanine-scanning mutagenesis. PMID:2471267
Additional Information

Study Summary

Number of data points 50
Proteins Somatotropin
Unique complexes 50
Assays/Quantities/Protocols Experimental Assay: Dissociation constants
Libraries Side chains in hGH that modulate binding to the hgH receptor

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Somatotropin P01241 SOMA_HUMAN
100.0 Somatotropin P58756 SOMA_PANTR
96.8 Somatotropin P33093 SOMA_MACMU
93.7 Somatotropin P58757 SOM2_PANTR
90.5 Somatotropin Q9GMB3 SOMA_CALJA
93.2 Somatotropin P01242 SOM2_HUMAN
90.5 Somatotropin P58343 SOMA_SAIBB