Three separate pathways in maintain phosphatidylcholine biosynthesis, which is required for symbiotic nitrogen fixation with clover.

Unlabelled: Phosphatidylcholine (PC) is critical for the nitrogen-fixing symbiosis between rhizobia and legumes. We characterized three PC biosynthesis pathways in and evaluated their impact on nitrogen fixation in clover nodules. In the presence of choline, a PC synthase catalyzes the condensation of cytidine diphosphate-diacylglycerol with choline to produce PC.

A Dynamic Water Channel Affects O Stability in [FeFe]-Hydrogenases.

[FeFe]-hydrogenases are capable of reducing protons at a high rate. However, molecular oxygen (O ) induces the degradation of their catalytic cofactor, the H-cluster, which consists of a cubane [4Fe4S] subcluster (4Fe ) and a unique diiron moiety (2Fe ). Previous attempts to prevent O -induced damage have focused on enhancing the protein's sieving effect for O by blocking the hydrophobic gas channels that connect the protein surface and the 2Fe .