Fig. 9.
An associative cell biology of metals.
A, The four allosteric end states of a metal sensor protein: apo-protein (P), metal-bound protein (PM), DNA-bound apo-protein (PD) and DNA-bound metal-protein ((PM)D). Metal (M) exchange occurs between the metal sensor protein and cellular buffer (B) via K5-K9 by an associative mechanism [57,93,211]. B, Proposed metal-acquisition by a metal-sensor protein (InrS, PDB 5FMN) from a cellular metal-buffer complex (Ni(II)His2, LHISNI01) via formation of a heterocomplex (modelled on PDB 4XKN). The Ni(II)-InrS model was generated using PDB 2HH7 plus free His (HIS_LFOH). InrS side chains are light blue, histidine from the cellular buffer is grey, nickel is green.