【多选题】What are posttranslational modifications of proteins ?
A.
In addition to folding properly, many proteins—once they leave the ribosome—require further adjustments before they are useful to the cell. Namely, many proteins require posttranslational modifications (PTMs) to become fully functional.
B.
To be useful to the cell, a completed polypeptide must fold correctly into its three-dimensional conformation and then bind any required cofactors and protein partners—all via noncovalent bonding.
C.
Many proteins also require one or more covalent modifications to become active—or to be recruited to specific membranes or organelles.
D.
Although phosphorylation and glycosylation are the most common, more than 100 types of covalent modifications of proteins are known.
【多选题】What is the structure of the SMC proteins (structural maintenance of chromosomes)?
A.
The primary structure of SMC proteins consists of five distinct domains.
B.
The amino- and carboxyl-terminal globular domains, N and C, each of which contains part of an ATP-hydrolytic site, are connected by two regions of α-helical coiled-coil motifs joined by a hinge domain.
C.
The proteins are generally dimeric, forming a V-shaped complex that is thought to be tied together through the protein’s hinge domains.
D.
One N and one C domain come together to form a complete ATP-hydrolytic site at each free end of the V.