3SLJ

Pre-cleavage Structure of the Autotransporter EspP - N1023A mutant

Summary for 3SLJ

• Entry DOI: 10.2210/pdb3slj/pdb
• Related: 3SLO 3SLT
• Descriptor: Serine protease espP, (HYDROXYETHYLOXY)TRI(ETHYLOXY)OCTANE (3 entities in total)
• Functional Keywords: beta barrel, membrane protein, asparagine cyclization, autocleavage, protein transport
• Biological source: Escherichia coli
• Cellular location: Serine protease EspP: Periplasm . Secreted autotransporter protein EspP: Secreted. Autotransporter protein EspP translocator: Cell outer membrane ; Multi-pass membrane protein : Q7BSW5
• Total number of polymer chains: 1
• Total formula weight: 37175.94

Authors

Barnard, T.B.,Noinaj, N.,Easley, N.C.,Kuszak, A.J.,Buchanan, S.K. (deposition date: 2011-06-24, release date: 2011-11-16, Last modification date: 2023-09-13)

Primary citation

Barnard, T.J.,Gumbart, J.,Peterson, J.H.,Noinaj, N.,Easley, N.C.,Dautin, N.,Kuszak, A.J.,Tajkhorshid, E.,Bernstein, H.D.,Buchanan, S.K.
Molecular basis for the activation of a catalytic asparagine residue in a self-cleaving bacterial autotransporter.
J.Mol.Biol., 415:128-142, 2012

PubMed Abstract: Autotransporters are secreted proteins produced by pathogenic Gram-negative bacteria. They consist of a membrane-embedded β-domain and an extracellular passenger domain that is sometimes cleaved and released from the cell surface. We solved the structures of three noncleavable mutants of the autotransporter EspP to examine how it promotes asparagine cyclization to cleave its passenger. We found that cyclization is facilitated by multiple factors. The active-site asparagine is sterically constrained to conformations favorable for cyclization, while electrostatic interactions correctly orient the carboxamide group for nucleophilic attack. During molecular dynamics simulations, water molecules were observed to enter the active site and to form hydrogen bonds favorable for increasing the nucleophilicity of the active-site asparagine. When the activated asparagine attacks its main-chain carbonyl carbon, the resulting oxyanion is stabilized by a protonated glutamate. Upon cleavage, this proton could be transferred to the leaving amine group, helping overcome a significant energy barrier. Together, these findings provide insight into factors important for asparagine cyclization, a mechanism broadly used for protein cleavage.

PubMed: 22094314
DOI: 10.1016/j.jmb.2011.10.049

Experimental method

X-RAY DIFFRACTION (2.481 Å)