'Radical SAM' enzymes generate catalytic radicals by combining a 4Fe-4S cluster and S-adenosylmethionine (SAM) in close proximity. We present the first crystal structure of a Radical SAM enzyme, that of HemN, the Escherichia coli oxygen-independent coproporphyrinogen III oxidase, at 2.07 A resolution. HemN catalyzes the essential conversion of coproporphyrinogen III to protoporphyrinogen IX dur...

S-Adenosylmethionine (SAM) is formed exclusively in the cytosol but plays a major role in plastids; SAM can either act as a methyl donor for the biogenesis of small molecules such as prenyllipids and macromolecules or as a regulator of the synthesis of aspartate-derived amino acids. Because the biosynthesis of SAM is restricted to the cytosol, plastids require a SAM importer. However, this tran...

Stromal interaction molecule 1 (STIM1) is an endoplasmic reticulum (ER)-membrane associated Ca(2+) sensor which activates store-operated Ca(2+) entry (SOCE). The homologue, STIM2 possesses a high sequence identity to STIM1 ( approximately 61%), while its role in SOCE seems to be distinct from that of STIM1. In order to understand the underlying mechanism for the functional differences between S...

The polycomb group proteins are required for the stable maintenance of gene repression patterns established during development. They function as part of large multiprotein complexes created via a multitude of protein-protein interaction domains. Here we examine the interaction between the SAM domains of the polycomb group proteins polyhomeotic (Ph) and Sex-comb-on-midleg (Scm). Previously we sh...

Résumé Entre Sam et Bram les lignes sont complexes couleurs varient. Amis compagnons, sur des chemins de traverse, ils se rencontrent dans leur conception absolue l’œuvre d’art. Beckett tente parler peintures y reconnaît (là aussi) un inévitable échec. lit aime s’y perdre.

BACKGROUND In hypertrophic cardiomyopathy, a spectrum of mitral leaflet abnormalities has been related to the mechanism of mitral systolic anterior motion (SAM), which causes both subaortic obstruction and mitral regurgitation. In the individual patient, SAM and regurgitation vary in parallel; clinically, however, great interindividual differences in mitral regurgitation can occur for comparabl...

This paper describes an experimentally simple method for assembling junctions with nanometer-scale, structured organic films positioned between two metal electrodes. These junctions comprise two metal electrodes that sandwich two self-assembled monolayers (SAMs) – that is, metal (mercury)–SAM//SAM–metal (mercury, gold or silver) junctions. The junctions are easy to assemble (because the mercury...