Key points are not available for this paper at this time.
INTRODUCTION AND O VERVIEW . . . . . . . . . .. . . . . . . .. . . . .. .. . . . . . 567 MECHAN ISM OF nif REGUL ATION 569 NifA and NtrC Require NtrA for Promoter Activation 569 NifA and NtrC are Structurally and Functionally Related 570 nif and ntr Promoters Have a Characteristic Primary Structure ....... 570 Role of NtrA in nif and ntr Gene Activation ........ ........ 571 Regulation of the glnA-ntrBC Operon 572 Regulation of NifA Synthesis and Activity in K. pneumoniae 574 Regulation of NifA Synthesis in R. meliloti 575 Mechanism of NifA Activation of nif Promoters 576 COMPARI SON OF N ifAlNtrC ACTI VATION WITH OTHER PO SITI VE REGUL ATORY SySTEM S ....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 580 New Sigma Factors 580 DNA-Binding Activator Proteins 581 Far Upstream Binding Sites 582 Significance of ntrinif Consensus Sequences 584 Homology of NtrC, NifA , and NtrB with Other Regulatory Proteins 584 CON CLUSION S........ . . . . .. ... ........ 585
Gussin et al. (Mon,) studied this question.