Article de synthese sur le metabolisme de la methionine, acide amine essentiel, chez les mammiferes. Etude du schema metabolique, de la regulation du metabolisme (mise en evidence et importance relative de chaque facteur). Etude de la transamination de la methionine, du role de la S-adenosyl-methionine, de l'oxydation de l'homocysteine et de la cystathionine. Etude du disfonctionnement du metabolisme et des consequences chez les hommes

Methionine metabolism in mammals.

Biology of DNA restriction.

Genome sequencing projects are predicting large numbers of novel proteins, whose interactions with other proteins must mediate the function of cellular processes. To analyse these networks, we used the yeast two-hybrid system on a genome-wide scale to identify 25 interactions among the proteins of Escherichia coli bacteriophage T7. Among these is a set of six interactions connecting proteins that function in DMA replication and DMA packaging. Remarkably, two genes, arranged such that one entirely overlaps the other and uses a different reading frame, encode interacting proteins. Several of the interactions reflect intramolecular associations of different domains of the same polypeptide, suggesting that the two-hybrid assay may be useful in the analysis of protein folding. This global approach to protein–protein interactions may be applicable to the analysis of more complex genomes whose sequences are becoming available.

A protein linkage map of Escherichia coli bacteriophage T7.

https://mmbr.asm.org/content/mmbr/47/3/345.full.pdf

Bacteriophage survival: multiple mechanisms for avoiding the deoxyribonucleic acid restriction systems of their hosts.

https://www.cell.com/molecular-cell/pdf/S1097-2765(02)00435-5.pdf

Structure of Ocr from bacteriophage T7, a protein that mimics B-form DNA.

Bacteriophage T3 and T7 protect their DNA from restriction by producing, as the earliest detectable phage functions, anti-restriction proteins Although the two phage proteins differ in their chromatographic and antigenic properties, they act by the same mechanism: the anti-restriction proteins inhibit E coli K12 restriction endonuclease by direct interaction

A novel bacteriophage defence mechanism: the anti-restriction protein.

Bacteriophage T3 induces an enzyme activity which hydrolyzes S-adenosylmethionine. This S-adenosylmethionine hydrolase is interesting, not only because of its unique activity, but also because the protein has to overcome host restriction [F. W. Studier and N. R. Movva (1976) J. Virol. 19, 136-145]. S-Adenosylmethionine hydrolase was purified to homogeneity using affinity chromatography on S-adenosylhomocysteine-Sepharose. The enzyme occurs in two forms, A and B. Form A consists of the viral peptide chain only; its native and subunit molecular weight is 17,000. Form B contains, in addition, a host subunit with a molecular weight of 49,000. The host subunit does not modify S-adenosylmethionine cleavage in vitro and no apparent relationship to the host-restriction system could be detected.

Nikolaus Spoerel

Papers

A novel bacteriophage defence mechanism: the anti-restriction protein.

Colivirus-T3-coded S-adenosylmethionine hydrolase