Conformation and molecular dynamics calculations on uteroglobin fragment 18-47

The conformational properties of fragment 18–47 of rabbit uteroglobin in aqueous solution containing SDS micelles were investigated by two-dimensional nmr spectroscopy and molecular dynamics calculations. The fragment comprises helices II and III and the β-turn connecting the two helices. The nmr results and nmr-restrained molecular dynamics calculations showed that in the isolated fragment the elements of secondary structure present in the intact protein are preserved only in part. Specifically, a well-defined α-helix was found in the sequence 33–44, corresponding to helix III of uteroglobin, while the regions of helix II and β-turn are characterized by high flexibility in the fragment. © 1994 John Wiley & Sons, Inc.