4NJN

Crystal Structure of E.coli GlpG at pH 4.5

Summary for 4NJN

• Entry DOI: 10.2210/pdb4njn/pdb
• Related: 2IC8 4NJP
• Descriptor: Rhomboid protease GlpG (2 entities in total)
• Functional Keywords: rhomboid protease, intramembrane proteolysis, membrane protein, hydrolase-membrane protein complex, hydrolase/membrane protein
• Biological source: Escherichia coli
• Cellular location: Cell inner membrane; Multi-pass membrane protein: P09391
• Total number of polymer chains: 1
• Total formula weight: 23816.13

Authors

Dickey, S.W.,Baker, R.P.,Cho, S.,Urban, S. (deposition date: 2013-11-11, release date: 2013-12-25, Last modification date: 2023-09-20)

Primary citation

Dickey, S.W.,Baker, R.P.,Cho, S.,Urban, S.
Proteolysis inside the Membrane Is a Rate-Governed Reaction Not Driven by Substrate Affinity.
Cell(Cambridge,Mass.), 155:1270-1281, 2013

PubMed Abstract: Enzymatic cleavage of transmembrane anchors to release proteins from the membrane controls diverse signaling pathways and is implicated in more than a dozen diseases. How catalysis works within the viscous, water-excluding, two-dimensional membrane is unknown. We developed an inducible reconstitution system to interrogate rhomboid proteolysis quantitatively within the membrane in real time. Remarkably, rhomboid proteases displayed no physiological affinity for substrates (K(d) ~190 μM/0.1 mol%). Instead, ~10,000-fold differences in proteolytic efficiency with substrate mutants and diverse rhomboid proteases were reflected in k(cat) values alone. Analysis of gate-open mutant and solvent isotope effects revealed that substrate gating, not hydrolysis, is rate limiting. Ultimately, a single proteolytic event within the membrane normally takes minutes. Rhomboid intramembrane proteolysis is thus a slow, kinetically controlled reaction not driven by transmembrane protein-protein affinity. These properties are unlike those of other studied proteases or membrane proteins but are strikingly reminiscent of one subset of DNA-repair enzymes, raising important mechanistic and drug-design implications.

PubMed: 24315097
DOI: 10.1016/j.cell.2013.10.053

Experimental method

X-RAY DIFFRACTION (2.4 Å)