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Biomedical subjects

M J Sternberg

Publications and source records attributed to M J Sternberg.

At least 127 records · Page 7Linked to original sources
PubMed1981

Analysis of structural similarities between brain Thy-1 antigen and immunoglobulin domains. Evidence for an evolutionary relationship and a hypothesis for its functional significance.

The Thy-1 membrane glycoprotein from rat brain is shown to have structural and sequence homologies with immunoglobulin (Ig) domains on the basis of the following evidence. 1. The two disulphide bonds of Thy-1 are both consistent with the Ig-fold. 2. The molecule contains extensive beta-structure as shown by the c.d. spectrum. 3. Secondary structure prediction locates beta-strands along the sequence in a manner consistent with the Ig-fold. 4. On the basis of rules derived from known beta-sheet structures, a three-dimensional structure with the Ig-fold is predicted as favourable for Thy-1. 5. Sequences in the proposed beta-strands of Thy-1 and known beta-strands of Ig domains show significant sequence homology. This homology is statistically more significant than for the comparison of proposed beta-strand sequences of beta 2-microglobulin with Ig domains. An hypothesis is presented for the possible functional significance of an evolutionary relationship between Thy-1 and Ig. It is suggested that both Thy-1 and Ig evolved from primitive molecules, with an Ig fold, which mediated cell--cell interactions. The present-day role of Thy-1 may be similar to that of the primitive domain.

Amino Acid Sequence↗
PubMed1980

The Clq receptor site on immunoglobulin G.

We propose that, the binding site for the complement subcomponent Clq on immunoglobulin G involves the last two (C-terminal) beta-strands of the C gamma 2 domain. This region contains a large number of accessible and highly conserved charged residues and charge is postulated as an important component of the Clq-IgG interaction. The conclusions are reached on the basis of accessibility and sequence conservation analyses of C gamma 2 amino acid residues, the use of specific inhibitors and chemical modification studies.

Amino Acid Sequence↗
PubMed1980

A diffusion--collision--adhesion model for the kinetics of myoglobin refolding.

There are two distinct experimental and theoretical problems of protein folding: the thermodynamic issue of characterizing the folded state, and the kinetic question of the path between the unfolded and native states. Here we consider the second question and present a diffusion--collision--adhesion model for the folding of the alpha-helical protein myoglobin. In particular, we consider the fast refolding species of the unfolded state and ignore the slow transition between unfolded states that has been attributed to proline isomerization.

Chemical Phenomena↗
PubMed1980

Analysis and prediction of protein beta-sheet structures by a combinatorial approach.

Analysis of beta-sheet sandwiches (for example immunoglobulin domains) suggests an algorithm that successfully predicts the tertiary fold of these proteins from their sequence and secondary structure. We propose tertiary structures for beta 2-microglobulin and an HLA-B7 antigen fragment. Topological rules are presented that markedly reduce the number of folds for proteins in which a-helices pack against a parallel beta-sheet.

Biological Evolution↗
PubMed1979

Crystallographic studies of the dynamic properties of lysozyme.

The patterns of atomic displacements in the crystals of hen and human lysozyme derived from independent crystallographic refinement are broadly similar. Analysis of the pattern indicates a close correlation with molecular structure, strongly suggestive of intramolecular motion. The active site of lysozyme is located in a region of high displacement. It is concluded that protein mobility may play a significant part in biological activity and that X-ray crystallography can contribute to its analysis.

Animals↗
PubMed1978

Prediction of protein structure from amino acid sequence.

In principle, it is possible to predict theoretically the three-dimensional structure of a protein from its amino acid sequence. Recently substantial progress towards this goal has been made by the use of simple models to represent protein conformation and interatomic interactions, together with the knowledge gained form analyses of know protein structures.

Amino Acid Sequence↗