BIOL 103 Lecture Notes - Lecture 13: Santa Barbara City College, Signal Peptidase, Signal Peptide
Document Summary
Pes of protein insertion into er: soluble proteins. Only needs a single transfer sequence: found at the n-terminus. The peptide moves through the translocation channel into the lumen of the er. Signal sequence remains embedded in the membrane and later cleaved off by a protein called the signal peptidase. Leaving the protein free in the lumen of the. Signal sequences located at the n-terminus is always cleaved off. N-terminal start sequences can be combined with other er signal sequences to produce. Orientation of a protein in the membrane is established when it is first inserted into the. As they begin translating when the first signal is encountered- known as start transfer sequence- and will continue to be translated until a second hydrophobic membrane crossing domain is encountered. The cytosolic side of the membrane remains on the cytosolic throughout all membrane processes. This is a stop transfer signal and leaves protein inserted in the er membrane.