2025 Hyper Recent •CC0 1.0 Universal

This work is dedicated to the public domain. No rights reserved.

Access Preprint From Server
April 3rd, 2025
Version: 1
National University of Singapore
biochemistry
biorxiv

Exquisite specificity of Pks13 defines the essentiality of trehalose in mycobacteria

Chen, Y.Open in Google Scholar•Lim, J. D. T.Open in Google Scholar•Chng, S.-S.Open in Google Scholar

Mycolic acids (MAs) are the major component of the mycobacterial outer membrane, a key contributor to the intrinsic resistance of mycobacteria to external insults, including multiple antibiotics. After being synthesized in the cytoplasm, MAs are transported across the cell envelope in a sugar-esterified form, generally believed to be trehalose monomycolates (TMMs). However, whether trehalose is the only mycolate carrier during transport is under debate, and why this highly abundant disaccharide is essential for mycobacterial growth is unclear. To address these questions, we leveraged a trehalose-auxotrophic Mycobacterium smegmatis strain to investigate the final biosynthetic steps affording TMMs. We show that in addition to TMMs, new MAs are also not produced in the absence of trehalose. During trehalose depletion, mycolate precursors accumulate on Pks13, the polyketide synthase catalyzing the condensation of MAs, and ligation to the sugar head group, possibly blocking the enzyme and preventing the synthesis of new mature MAs. We establish that the native mycolate precursors can only be released by trehalose in vitro, and subsequently processed in a final reduction step. Furthermore, we demonstrate that only trehalose can re-activate MA biosynthesis in trehalose-depleted cells. Our work reveals the exquisite specificity of Pks13 for trehalose, providing a compelling reason for the its essentiality in mycobacteria, as well as new ideas towards the future development of anti-mycobacterial strategies.

Similar Papers

biorxiv
Fri Apr 04 2025
Membrane curvature regulates Ups1 dependent phosphatidic acid transfer across lipid bilayers
Mitochondria are essential organelles in eukaryotic cells, enclosed by two membranes with distinct compositions and functions. In addition to the endoplasmic reticulum, mitochondria are major sites of cellular lipids production. Cardiolipin, for example, is exclusively synthesized in the mitochondrial inner membrane. This requires the precursor lipid phosphatidic acid to be imported from the endop...
Sadeqi, F.
•
Dong, D.
•
Stroh, K.
•
Vache, M.
...•
Meinecke, M.
biorxiv
Fri Apr 04 2025
Development and Clinical Evaluation of a Multiplexed Health Surveillance Panel Using Ultra High-Throughput PRM-MS in an Inflammatory Bowel Disease Cohort.
Despite advances in clinical proteomics, translating protein biomarker discoveries into clinical use remains challenging due to the technical complexity of the validation process. Targeted MS-based proteomics approaches such as parallel reaction monitoring (PRM) offer sensitive and specific assays for biomarker translation. In this study, we developed a multiplex PRM assay using the Stellar mass s...
Fu, Q.
•
Remes, P. M.
•
Lee, J.
•
Jacob, C.
...•
Van Eyk, J. E.
biorxiv
Thu Apr 03 2025
Development of pyrazolopyrimidine based macrocyclic kinase inhibitors targeting AAK1
Since the outbreak of SARS-CoV-2 in recent years, our society has become more aware that zoonotic diseases pose a real threat. Therefore, the demand for small molecules that target host proteins, essential for viral entry and replication, has increased as an interesting strategy for the development of antiviral agents, as these agents may be effective against several different pathogens. NAK kinas...
Mensing, T. E.
•
Kurz, C. G.
•
Amrhein, J. A.
•
Ehret, T. A. L.
...•
Hanke, T.
biorxiv
Thu Apr 03 2025
Pooled scanning of protein variants identifies novel RNA-binding mutants
Binding to RNA has been observed for an ever-increasing number of proteins, which often have other functions. The contributions of RNA binding to protein function are best discerned by studying separation-of-function mutants that hamper interaction with RNA without affecting other aspects of protein function. To design these mutants, we need precise knowledge of the residues that contribute to the...
Tasca, J. A.
•
Doherty, J. F.
•
Shields, E. J.
•
Dissanayaka Mudiyanselage, S.
...•
Bonasio, R.
biorxiv
Thu Apr 03 2025
The MAP2Ks can use ADP to phosphorylate and activate their substrate MAPKs in vitro
Kinases are a diverse group of enzymes that use ATP to phosphorylate a variety of substrates. Protein kinases evolved in eukaryotes as important mediators of cell signalling that target specific amino acid side chains to modulate downstream protein function. Among them, the MAPKs (mitogen-activated protein kinases) are a family of intracellular protein kinases that form signalling cascades respond...
Juyoux, P.
•
von Velsen, J.
•
Pellegrini, E.
•
Bowler, M. W.
biorxiv
Thu Apr 03 2025
The sialylation pattern of dietary glycopeptides is vital for inhibiting pathogens and modulating gut microbiota in elderly individuals
N-glycosylation is a post-translational modification of proteins that can influence the structure and function of glycoproteins. Edible bird\'s nest (EBN) contains highly sialylated mucins with N-glycans and O-glycans, while casein glycomacropeptide (CGMP) is modified with only O-glycans. We prepare EBN sialoglycopeptides through sequential protease treatment and their inhibitory effects on pathog...
Zhu, J.
•
Zhang, T.
•
Wu, J.
•
Zhang, H.
biorxiv
Thu Apr 03 2025
Zinc stimulation of phytoplankton in a low carbon dioxide, coastal Antarctic environment: evidence for the Zn hypothesis
The ocean acts as a carbon sink, absorbing carbon from the atmosphere and resulting in substantial uptake of anthropogenic CO2 emissions. As biological processes in the oceans such as net primary production (NPP) contribute significantly to this sink, understanding how they will shift in response to increasing atmospheric CO2 is necessary to project future ocean carbon storage capacity. Macronutri...
Kell, R. M.
•
Subhas, A. V.
•
Schanke, N. L.
•
Lees, L. E.
...•
Saito, M. A.
biorxiv
Thu Apr 03 2025
Effect of the S2' site cleavage on SARS-CoV-2 spike
SARS-CoV-2 initiates infection of host cells by fusing its envelope lipid bilayer with the cell membrane. To overcome kinetic barriers for membrane fusion, the virus-encoded spike (S) protein refolds from a metastable prefusion state to a lower energy, stable postfusion conformation. The protein is first split into S1 and S2 fragments at a proteolytic site after synthesis, and presumably further c...
Shi, W.
•
Jonaid, G.
•
Kibria, M. G.
•
Allen, J.
...•
Chen, B.
biorxiv
Wed Apr 02 2025
Phosphate-binding pocket on cyclin B governs CDK substrate phosphorylation and mitotic timing
Cell cycle progression is governed by complexes of the cyclin-dependent kinases (CDKs) and their regulatory subunits cyclin and Cks1. CDKs phosphorylate hundreds of substrates, often at multiple sites. Multisite phosphorylation depends on Cks1, which binds initial priming phosphorylation sites to promote secondary phosphorylation at other sites. Here, we describe a similar role for a recently disc...
Ng, H. Y.
•
Whelpley, D. H.
•
Adly, A. N.
•
Maxwell, R. A.
•
Morgan, D. O.