Crystal Structure of the Neisseria gonorrhoeae MtrD Inner Membrane Multidrug Efflux Pump

Abstract

Neisseria gonorrhoeae is an obligate human pathogen and the causative agent of the sexually-transmitted disease gonorrhea. The control of this disease has been compromised by the increasing proportion of infections due to antibiotic-resistant strains, which are growing at an alarming rate. The MtrCDE tripartite multidrug efflux pump, belonging to the hydrophobic and amphiphilic efflux resistance-nodulation-cell division (HAE-RND) family, spans both the inner and outer membranes of N. gonorrhoeae and confers resistance to a variety of antibiotics and toxic compounds. We here report the crystal structure of the inner membrane MtrD multidrug efflux pump, which reveals a novel structural feature that is not found in other RND efflux pumps.

The Structure and Interactions of Periplasmic Domains of Crucial MmpL Membrane Proteins from Mycobacterium tuberculosis

“…The MmpL Cluster II topology suggests that periplasmic D1 and D2 domains interact, as observed in the structures of known RND transporters (Bolla, et al, 2014; Long, et al, 2010; Murakami, et al, 2002; Pak, et al, 2013; Sennhauser, et al, 2009). To test for stable interactions between MmpL3/11 D1 and D2 domains, purified recombinant MmpL3 or MmpL11 D1 and D2 domains were mixed together and then analyzed by size exclusion chromatography.…”

“…Thus, MmpL11-D2 was structurally aligned with AcrB (PDB code: 3W9H), CusA (PDB code: 4DNT), MexB (PDB code: 2V50), ZneA (PDB code: 4K0E), and MtrD (PDB code: 4MT1) (Bolla, et al, 2014; Nakashima, et al, 2013; Pak, et al, 2013; Sennhauser, et al, 2009; Su, et al, 2012) using RaptorX (Wang, et al, 2013). Of the approximately 1000 residues of the RND transporters, MmpL11-D2 aligns to the conserved porter subdomains, with an RMSD range of 2.0 – 2.9 Å over 69 – 74 Cα atoms.…”

Structure and Function of Neisseria gonorrhoeae MtrF Illuminates a Class of Antimetabolite Efflux Pumps

“…This system is similar to other efflux pumps of the resistance-nodulation-cell division (RND) superfamily (Tseng et al, 1999) possessed by many Gram-negative bacteria. MtrD (Bolla et al, 2014; Hagman et al, 1995; Hagman and Shafer, 1995; Hagman et al, 1997) is the inner membrane transporter component of the tripartite RND pump. The complex is formed by interactions between MtrD, the periplasmic membrane fusion protein MtrC (Hagman et al, 1995; Hagman et al, 1997; Veal et al, 2002; Janganan et al, 2013), and the outer membrane channel MtrE (Delahay et al, 1997; Lei et al, 2014; Janganan et al, 2011; Janganan et al, 2013).…”

Crystallization of Membrane Proteins by Vapor Diffusion

“…6b). 49 Analysis of the Matthews coefficient indicated the presence of one MtrD molecule (113.69 kDa) per asymmetric unit, with a solvent content of 66.7%. The final crystal structure of the MtrD transporter was determined to a resolution of 3.5 Å.…”

“…The most common and successful method of membrane protein crystallization, to date, this approach has allowed researchers in our lab to determine the crystal structures of a number of membrane proteins. These include the inner membrane efflux pumps CusA, 47 AcrB, 48 and MtrD, 49 the outer membrane channels CusC, 50 MtrE, 51 and CmeC, 52 as well as the CusBA adaptor-transporter efflux complex. 53 …”