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Dietrich C, Li de la Sierra-Gallay I, Masi M, Girard E, Dautin N, Constantinesco-Becker F, Tropis M, Daffé M, van Tilbeurgh H, Bayan N. The C-terminal domain of Corynebacterium glutamicum mycoloyltransferase A is composed of five repeated motifs involved in cell wall binding and stability. Mol Microbiol 2020; 114:1-16. [PMID: 32073722 DOI: 10.1111/mmi.14492] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 02/07/2020] [Indexed: 12/29/2022]
Abstract
The genomes of Corynebacteriales contain several genes encoding mycoloyltransferases (Myt) that are specific cell envelope enzymes essential for the biogenesis of the outer membrane. MytA is a major mycoloyltransferase of Corynebacterium glutamicum, displaying an N-terminal domain with esterase activity and a C-terminal extension containing a conserved repeated Leu-Gly-Phe-Pro (LGFP) sequence motif of unknown function. This motif is highly conserved in Corynebacteriales and found associated with cell wall hydrolases and with proteins of unknown function. In this study, we determined the crystal structure of MytA and found that its C-terminal domain is composed of five LGFP motifs and forms a long stalk perpendicular to the N-terminal catalytic α/β-hydrolase domain. The LGFP motifs are composed of a 4-stranded β-fold and occupy alternating orientations along the axis of the stalk. Multiple acetate binding pockets were identified in the stalk, which could correspond to putative ligand-binding sites. By using various MytA mutants and complementary in vitro and in vivo approaches, we provide evidence that the C-terminal LGFP domain interacts with the cell wall peptidoglycan-arabinogalactan polymer. We also show that the C-terminal LGFP domain is not required for the activity of MytA but rather contributes to the overall integrity of the cell envelope.
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Affiliation(s)
- Christiane Dietrich
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Ines Li de la Sierra-Gallay
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Muriel Masi
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Eric Girard
- University of Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Nathalie Dautin
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | | | - Maryelle Tropis
- Institut de Pharmacologie et de Biologie Structurale, CNRS UMR 5089, Toulouse Cedex, France
| | - Mamadou Daffé
- Institut de Pharmacologie et de Biologie Structurale, CNRS UMR 5089, Toulouse Cedex, France
| | - Herman van Tilbeurgh
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Nicolas Bayan
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
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Goins CM, Dajnowicz S, Smith MD, Parks JM, Ronning DR. Mycolyltransferase from Mycobacterium tuberculosis in covalent complex with tetrahydrolipstatin provides insights into antigen 85 catalysis. J Biol Chem 2018; 293:3651-3662. [PMID: 29352107 PMCID: PMC5846135 DOI: 10.1074/jbc.ra117.001681] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Indexed: 01/07/2023] Open
Abstract
Mycobacterium tuberculosis antigen 85 (Ag85) enzymes catalyze the transfer of mycolic acid (MA) from trehalose monomycolate to produce the mycolyl arabinogalactan (mAG) or trehalose dimycolate (TDM). These lipids define the protective mycomembrane of mycobacteria. The current model of substrate binding within the active sites of Ag85s for the production of TDM is not sterically and geometrically feasible; additionally, this model does not account for the production of mAG. Furthermore, this model does not address how Ag85s limit the hydrolysis of the acyl-enzyme intermediate while catalyzing acyl transfer. To inform an updated model, we obtained an Ag85 acyl-enzyme intermediate structure that resembles the mycolated form. Here, we present a 1.45-Å X-ray crystal structure of M. tuberculosis Ag85C covalently modified by tetrahydrolipstatin (THL), an esterase inhibitor that suppresses M. tuberculosis growth and mimics structural attributes of MAs. The mode of covalent inhibition differs from that observed in the reversible inhibition of the human fatty-acid synthase by THL. Similarities between the Ag85-THL structure and previously determined Ag85C structures suggest that the enzyme undergoes structural changes upon acylation, and positioning of the peptidyl arm of THL limits hydrolysis of the acyl-enzyme adduct. Molecular dynamics simulations of the modeled mycolated-enzyme form corroborate the structural analysis. From these findings, we propose an alternative arrangement of substrates that rectifies issues with the previous model and suggest a direct role for the β-hydroxy of MA in the second half-reaction of Ag85 catalysis. This information affords the visualization of a complete mycolyltransferase catalytic cycle.
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Affiliation(s)
- Christopher M. Goins
- From the Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606-3390
| | - Steven Dajnowicz
- From the Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606-3390, ,Biology and Soft Matter Division and
| | - Micholas D. Smith
- University of Tennessee and Oak Ridge National Laboratory (UT/ORNL) Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, and ,Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Jerry M. Parks
- University of Tennessee and Oak Ridge National Laboratory (UT/ORNL) Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, and
| | - Donald R. Ronning
- From the Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606-3390, , To whom correspondence should be addressed:
Dept. of Chemistry and Biochemistry, University of Toledo, 2801 W. Bancroft St., Toledo, OH 43606-3390. Tel.:
419-530-1585; E-mail:
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