Cross-Coupling of Mo- and V-Nitrogenases Permits Protein-Mediated Protection from Oxygen Deactivation.

Nitrogenases catalyze dinitrogen (N) fixation to ammonia (NH). While these enzymes are highly sensitive to deactivation by molecular oxygen (O) they can be produced by obligate aerobes for diazotrophy, necessitating a mechanism by which nitrogenase can be protected from deactivation. In the bacterium Azotobacter vinelandii, one mode of such protection involves an O-responsive ferredoxin-type protein ("Shethna protein II", or "FeSII") which is thought to bind with Mo-dependent nitrogenase's two component proteins (NifH and NifDK) to form a catalytically stalled yet O-tolerant tripartite protein complex.

The Mononuclear Metal-Binding Site of Mo-Nitrogenase Is Not Required for Activity.

The biological N-fixation process is catalyzed exclusively by metallocofactor-containing nitrogenases. Structural and spectroscopic studies highlighted the presence of an additional mononuclear metal-binding (MMB) site, which can coordinate Fe in addition to the two metallocofactors required for the reaction. This MMB site is located 15-Å from the active site, at the interface of two NifK subunits.

Nitrogen Fixation and Hydrogen Evolution by Sterically Encumbered Mo-Nitrogenase.

The substrate-reducing proteins of all nitrogenases (MoFe, VFe, and FeFe) are organized as αß(γ) multimers with two functional halves. While their dimeric organization could afford improved structural stability of nitrogenases , previous research has proposed both negative and positive cooperativity contributions with respect to enzymatic activity. Here, a 1.

Community-Led Health Promotion Groups in a Bhutanese-Nepali Refugee Community.

This practice note reports on the work of the Namaste Community Health Partnership, an academic-community partnership established to address health disparities in a metro-area Bhutanese-Nepali refugee community in the western United States. Partners worked together to develop, implement, and evaluate a culturally-tailored health promotion program where Bhutanese-Nepali individuals led weekly walking groups and shared health promotion information and behavior change tools with community participants. The program was implemented with approximately 70 community members across two metro-area neighborhoods and two adult day care centers serving elders.

From ZeRO to HeRO: Saving lives one HeRO at a time.

Introduction: This case report intends to highlight the Haemodialysis Reliable Outflow (HeRO) graft as a potential long term option for ongoing dialysis in patients with central venous stenosis.

Presentation Of Case: A 55year old patient, who developed end stage renal failure (ESRF) after chemotherapy treatment for breast cancer, presented at the limit of her dialysis access after a 15year haemodialysis history causing central vein stenosis. The patient was initially started on peritoneal dialysis but after repeated peritonitis was switched to haemodialysis.