degQ, Periplasmic pH-dependent serine endoprotease DegQ
Enzyme Classification 220.127.116.11
Also Known as
DEGQ_ECOLI, degQ, hhoA
DegQ could degrade transiently denatured and unfolded proteins which accumulate in the periplasm following stress conditions. DegQ is efficient with Val-Xaa and Ile-Xaa peptide bonds, suggesting a preference for a beta-branched side chain amino acids. Only unfolded proteins devoid of disulfide bonds appear capable to be cleaved, thereby preventing non-specific proteolysis of folded proteins. DegQ can substitute for the periplasmic protease DegP. DegQ can reversibly switch between different oligomeric forms that represent inactive (6-mer) and active (12-and 24-mer) protease states. Substrate binding triggers the conversion of the resting DegQ trimer and hexamer into catalytically active 12- and 24-mers. The conversion of 6-mer (DegQ6) into 12-mer (DegQ12) or 24-mer (DegQ24) is crucial in regulating protease activity.