Preprotein translocase, SecY subunit; The central subunit of the protein translocation channel SecYEG. Consists of two halves formed by TMs 1-5 and 6-10. These two domains form a lateral gate at the front which open onto the bilayer between TMs 2 and 7, and are clamped together by SecE at the back. The channel is closed by both a pore ring composed of hydrophobic SecY resides and a short helix (helix 2A) on the extracellular side of the membrane which forms a plug. The plug probably moves laterally to allow the channel to open. The ring and the pore may move independently.

Protein-export membrane protein, putative; Part of the Sec protein translocase complex. Interacts with the SecYEG preprotein conducting channel. SecDF uses the proton motive force (PMF) to complete protein translocation after the ATP-dependent function of SecA; Belongs to the SecD/SecF family. SecD subfamily.

Preprotein translocase, SecA subunit; Part of the Sec protein translocase complex. Interacts with the SecYEG preprotein conducting channel. Has a central role in coupling the hydrolysis of ATP to the transfer of proteins into and across the cell membrane, serving as an ATP-driven molecular motor driving the stepwise translocation of polypeptide chains across the membrane.

Ribosomal protein L11; Forms part of the ribosomal stalk which helps the ribosome interact with GTP-bound translation factors.

Transcription antitermination protein NusG; Participates in transcription elongation, termination and antitermination.

Ribosomal protein L33; Binds the 23S rRNA and the E site tRNA; Belongs to the bacterial ribosomal protein bL33 family.

Ribosomal protein L1; Binds directly to 23S rRNA. Forms the L1 stalk. Unlike the case in the Thermus thermophilus 70S ribosome, this protein is not seen to block the exit path of the E site tRNA. It is clear that the protein in the structure is flexible however, so this is probably due to its position in these crystals.

Inner membrane protein, 60 kDa, putative; Required for the insertion and/or proper folding and/or complex formation of integral membrane proteins into the membrane. Involved in integration of membrane proteins that insert both dependently and independently of the Sec translocase complex, as well as at least some lipoproteins. Aids folding of multispanning membrane proteins (By similarity).

Signal recognition particle protein; Involved in targeting and insertion of nascent membrane proteins into the cytoplasmic membrane. Binds to the hydrophobic signal sequence of the ribosome-nascent chain (RNC) as it emerges from the ribosomes. The SRP-RNC complex is then targeted to the cytoplasmic membrane where it interacts with the SRP receptor FtsY. Belongs to the GTP-binding SRP family. SRP54 subfamily.