1. School of Chemical and Life Sciences, University of Greenwich, Woolwich Campus, Wellington Street, Woolwich, London SE18 6PF, U.K., Department of Biological Sciences, Central Campus, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K., Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany, Nitrogen Fixation Laboratory, John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, U.K., and School of Chemistry, Physics and Environmental Science, University of Sussex,...