Fig. 5.

The presequence associated motor (PAM). a PAM architecture. Hsp70 is in its ATP-bound state, with cleft easily accessible for binding an incoming polypeptide that would enter through the Tim23 channel, as indicated by the arrow. Tim50, an essential component of the TIM23 translocon with an essential inter membrane space (IMS) domain, is not shown. Likewise, the N-terminal IMS-localized domain of Tim23 is not shown. Both interact with presequence prior to its entering the channel. The nucleotide exchange factor (NEF) Mge1 is not shown; it interacts with ADP-bound Hsp70, not the ATP-bound form that is present at the translocon. b Components shown in a are depicted individually. Interactions to particular domains observed by biochemical, structural, or site-specific crosslinking experiments are indicated with a dash. Matrix exposed loops of Tim17 and Tim23 are indicated by number (“1” and “3”). The N-terminal and C-terminal domains (NTD and CTD, respectively) of Tim44 are shown; NTD is represented as a “cloud” to indicate that it is intrinsically disordered