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G H Goodwin

Publications and source records attributed to G H Goodwin.

80 records · Page 5Linked to original sources
PubMed1976

Physical studies of the nonhistone chromosomal proteins HMG-U and HMG-2.

The nonhistone chromosomal proteins, HMG-1 and HMG-2, have a folded conformation, with a high alpha-helical content, over a wide pH range. At high and low pH values, the molecules unfold. Both molecules contain cysteine and tryptophan. The tryptophans appear to be buried in the folded form. HMG-1 shows aggregation at pH 5.7, as does HMG-2 at pH 9.0. The folded form is insensitive to high concentrations of salt, suggesting that charge-charge interaction plays no role in stabilizing the tertiary structure.

Animals↗
PubMed1976

The similarity between the primary structures of two non-histone chromosomal proteins.

A comparison has been made of two non-histone chromosomal proteins, high-mobility-group proteins 1 and 2. Peptides produced from the two proteins by various chemical and enzymic cleavages have been compared by polyacrylamide gel electrophoresis and peptide mapping. In addition the cysteine content, C-terminal sequences and amide content have been determined for both proteins. The results obtained, together with previous results, show that high-mobility-group proteins 1 and 2 have closely related primary structures, although obviously being different molecules. When analysed by isoelectric focusing both proteins exhibit complex banding patterns. In the case of high-mobility-group protein 1, this could be caused by aggregation, but with high-mobility-group protein 2 there are four distinctive subfractions focusing between pH 7.8 and 8.9.

Amides↗
PubMed1976

Conformational studies of two non-histone chromosomal proteins and their interactions with DNA.

The conformational properties of two non-histone chromosomal proteins (high-mobility-group proteins 1 and 2) have been studied by spectroscopic methods. The interaction of high-mobility-group protein 1 with DNA has also been studied. 1. Circular dichroism results indicate that in the presence of salt both proteins are 40-50% helical between pH 1 and 9. Above pH 9 denaturation takes place. In the absence of salt the proteins denature below pH 4. 2. Nuclear magnetic resonance spectra show the presence of ring-current shifted peaks and perturbed aromatic resonances, demonstrating that the helix formation is accompanied by specific tertiary folding. 3. Nuclear magnetic resonance spectra of compelxes between high mobility group protein 1 and DNA demonstrate that a low ionic strength a portion of the molecule rich in lysine and containing all the aromatic residues is bound to DNA, whilst a more acidic region of the chain remains free from the DNA.

Animals↗
PubMed1975

An improved large scale fractionation of high mobility group non-histone chromatin proteins.

1. Methodology is presented for the large scale preparation and fractionation of high mobility group proteins from calf thymus chromatin. The total high mobility group protein from approx. 1 kg calf thymus tissue can be separated into five fractions by CM-Sephadex C25 ion-exchange chromatography. High mobility group proteins 1 and 2 comprise two fo the fractions. From a third fraction two more chromatin proteins, protein 3 and 17, can be isolated by trichloroacetic acid precipitation and CM-cellulose chromatography at pH 5.5. 2. The four proteins thus purified are lysine-rich proteins. Proteins 1 and 2 are additionally characterised by their high contents of acidic amino acids, as described previously (Goodwin, G. H. and Johns, E. W. (1973) Eur. J. Biochem. 40, 215-219). Proteins 3 and 17, having lower contents of acidic amino acids, are basic proteins similar to the histones. All four proteins exhibit single N-terminal amino acids; glycine is the N-terminal group of proteins 1, 2 and 3; protein 17 has a proline N-terminal amino acid. The proteins are not highly phosphorylated nor are they associated with appreciable quantities of nucleic acid.

Amino Acids↗
PubMed1975

Interaction of a non-histone chromatin protein (high-mobility group protein 2) with DNA.

1. The interaction with DNA of the calf thymus chromatin non-histone protein termed the high-mobility group protein 2 has been studied by sedimentation analysis in the ultracentrifuge and by measuring the binding of the 125I-labelled protein to DNA. The results have been compared with those obtained previously by us [Eur. J. Biochem. (1974) 47, 263-270] for the interaction of high-mobility group protein 1 with DNA. Although the binding parameters are similar for these two proteins, high-mobility group protein 2 differs from high-mobility group protein 1 in that the former appears to change the shape of the DNA to a more compact form. 2. The molecular weight of high-mobility group protein 2 has been determined by equilibrium sedimentation and a mean value of 26 000 was obtained. 3. A low level of nuclease activity detected in one preparation of high-mobility group protein 2 has been investigated.

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