Dear CCP4BB comunnity; I am not a structural biologist thus far.
I would like to inquire about the concept of quaternary structure and its applicability to the system I am currently investigating. The protein under study is a human lysosomal protein (Gene MAN2B1) that initially presents as a single chain. Upon entry into the lysosome (facilitated by the signal peptide), it undergoes cleavage four times in four external loops, resulting in the formation of five different "chains." The tertiary structure remains unchanged, and only after denaturation and purification, it becomes possible to observe the five distinct peptides. If the protein remains in the endoplasmic reticulum (ER), it exists as a single chain, as there is no cleavage due to the higher pH in the ER. My question is as follows: can we consider the protein inside the lysosome as having a quaternary structure? It originates from a monomer, and the subunits exhibit different sequences while interacting with each other. But indeed, there are 5 different peptides. I would appreciate your expertise and consideration of this perhaps unconventional question, which is causing me significant concern. Best regards, Bruno Di Geronimo. ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/
