Ammonia permeability of the soybean nodulin 26 channel

作者：Hwang Jin Ha; Ellingson Sally R; Roberts Daniel M^*

来源：FEBS LETTERS, 2010, 584(20): 4339-4343.

DOI：10.1016/j.febslet.2010.09.033

• Nitrogen fixation
• Aquaporin
• Symbiosis
• Legume

Soybean nodulin 26 (nod26), a member of the aquaporin superfamily, is the major protein component of the symbiosome membrane that encloses nitrogen-fixing bacteroids in root nodules. Previous work has demonstrated that nod26 facilitates the transport of water and glycerol, although a potential additional role as a channel for fixed ammonia efflux has been hypothesized. In the present study it is shown that recombinant nod26 reconstituted into proteoliposomes facilitates NH(3) transport in an Hg(2+)-sensitive manner with a reduced activation energy, hallmarks of protein-facilitated transport characteristic of aquaporins. Comparison of the predicted single-channel transport rates of nod26 suggests a 4.9-fold preference for ammonia compared to water.

• 出版日期2010-10-22