title: Conformation and domain structure of the non-histone chromosomal proteins HMG 1 and 2. Domain interactions.
abstract: The sequence of the 224 residues of HMG 1 suggests it consists of three domains. We have previously proposed [Cary et al. (1980 Eur. J. Biochem. 131, 367-374] that the A and B domains can fold autonomously and that there is also a small N domain. Several proteases are now found to cut at the end of the B domain (at or close to residue 184). It is shown that the A + B-domain fragment also folds and probably contains all the helix of intact HMG 1. The stability of the B domain is enhanced by the presence of the A domain. The acidic C domain undergoes a coil----helix transition on lowering the pH. Several peptides have been prepared by cleavage at tryptophan. Peptide 57--C-terminus contains complete B and C domains but does not fold. In the absence of the A domain the C domain is thus able to destabilise the B domain. It is concluded that the stability of the B domain in HMG 1 is due to interaction with the A domain and the C domain has a separate function from the other domains.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D055598:Chemical Phenomena; D002621:Chemistry; D002868:Chromosomal Proteins, Non-Histone; D002942:Circular Dichroism; D006609:High Mobility Group Proteins; D009682:Magnetic Resonance Spectroscopy; D010446:Peptide Fragments / Q000302:isolation & purification; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D000596:Amino Acids; D002868:Chromosomal Proteins, Non-Histone; D006609:High Mobility Group Proteins; D010446:Peptide Fragments