Complex structure of the acyltransferase VinK and the carrier protein VinL with a pantetheine cross-linking probe

Author(s):  
Akimasa Miyanaga ◽  
Risako Ouchi ◽  
Fumitaka Kudo ◽  
Tadashi Eguchi

Acyltransferases are responsible for the selection and loading of acyl units onto carrier proteins in polyketide and fatty-acid biosynthesis. Despite the importance of protein–protein interactions between the acyltransferase and the carrier protein, structural information on acyltransferase–carrier protein interactions is limited because of the transient interactions between them. In the biosynthesis of the polyketide vicenistatin, the acyltransferase VinK recognizes the carrier protein VinL for the transfer of a dipeptidyl unit. The crystal structure of a VinK–VinL covalent complex formed with a 1,2-bismaleimidoethane cross-linking reagent has been determined previously. Here, the crystal structure of a VinK–VinL covalent complex formed with a pantetheine cross-linking probe is reported at 1.95 Å resolution. In the structure of the VinK–VinL–probe complex, the pantetheine probe that is attached to VinL is covalently connected to the side chain of the mutated Cys106 of VinK. The interaction interface between VinK and VinL is essentially the same in the two VinK–VinL complex structures, although the position of the pantetheine linker slightly differs. This structural observation suggests that interface interactions are not affected by the cross-linking strategy used.

2016 ◽  
Vol 113 (7) ◽  
pp. 1802-1807 ◽  
Author(s):  
Akimasa Miyanaga ◽  
Shohei Iwasawa ◽  
Yuji Shinohara ◽  
Fumitaka Kudo ◽  
Tadashi Eguchi

Acyltransferases (ATs) are key determinants of building block specificity in polyketide biosynthesis. Despite the importance of protein–protein interactions between AT and acyl carrier protein (ACP) during the acyltransfer reaction, the mechanism of ACP recognition by AT is not understood in detail. Herein, we report the crystal structure of AT VinK, which transfers a dipeptide group between two ACPs, VinL and VinP1LdACP, in vicenistatin biosynthesis. The isolated VinK structure showed a unique substrate-binding pocket for the dipeptide group linked to ACP. To gain greater insight into the mechanism of ACP recognition, we attempted to crystallize the VinK–ACP complexes. Because transient enzyme–ACP complexes are difficult to crystallize, we developed a covalent cross-linking strategy using a bifunctional maleimide reagent to trap the VinK–ACP complexes, allowing the determination of the crystal structure of the VinK–VinL complex. In the complex structure, Arg-153, Met-206, and Arg-299 of VinK interact with the negatively charged helix II region of VinL. The VinK–VinL complex structure allows, to our knowledge, the first visualization of the interaction between AT and ACP and provides detailed mechanistic insights into ACP recognition by AT.


2020 ◽  
Author(s):  
Michael Burkart ◽  
Thomas Bartholow ◽  
Terra Sztain ◽  
Ashay Patel ◽  
D Lee ◽  
...  

Abstract Fatty acid biosynthesis (FAB) is an essential and highly conserved metabolic pathway. In bacteria, this process is mediated by an elaborate network of protein•protein interactions (PPIs) involving a small, dynamic acyl carrier protein that interacts with dozens of other partner proteins (PPs). These PPIs have remained poorly characterized due to their dynamic and transient nature. Using a combination of solution-phase NMR spectroscopy and protein-protein docking simulations, we report a comprehensive residue-by-residue comparison of the PPIs formed during FAB in Escherichia coli. This work reveals the molecular basis of six discrete binding events responsible for E. coli FAB and offers insights into a method to characterize these events and those in related carrier protein-dependent pathways. ONE SENTENCE SUMMARY: Through a combination of structural and computational analysis, a comparative evaluation of protein-protein interactions in de novo fatty acid biosynthesis in E. coli is performed.


2015 ◽  
Vol 13 (17) ◽  
pp. 5030-5037 ◽  
Author(s):  
Anthony M. Burke ◽  
Wynne Kandur ◽  
Eric J. Novitsky ◽  
Robyn M. Kaake ◽  
Clinton Yu ◽  
...  

The cross-linking Mass Spectrometry (XL-MS) technique extracts structural information from protein complexes without requiring highly purified samples, crystallinity, or large amounts of material.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Thomas G. Bartholow ◽  
Terra Sztain ◽  
Ashay Patel ◽  
D. John Lee ◽  
Megan A. Young ◽  
...  

AbstractFatty acid biosynthesis (FAB) is an essential and highly conserved metabolic pathway. In bacteria, this process is mediated by an elaborate network of protein•protein interactions (PPIs) involving a small, dynamic acyl carrier protein that interacts with dozens of other partner proteins (PPs). These PPIs have remained poorly characterized due to their dynamic and transient nature. Using a combination of solution-phase NMR spectroscopy and protein-protein docking simulations, we report a comprehensive residue-by-residue comparison of the PPIs formed during FAB in Escherichia coli. This technique describes and compares the molecular basis of six discrete binding events responsible for E. coli FAB and offers insights into a method to characterize these events and those in related carrier protein-dependent pathways.


2020 ◽  
Vol 27 (37) ◽  
pp. 6306-6355 ◽  
Author(s):  
Marian Vincenzi ◽  
Flavia Anna Mercurio ◽  
Marilisa Leone

Background:: Many pathways regarding healthy cells and/or linked to diseases onset and progression depend on large assemblies including multi-protein complexes. Protein-protein interactions may occur through a vast array of modules known as protein interaction domains (PIDs). Objective:: This review concerns with PIDs recognizing post-translationally modified peptide sequences and intends to provide the scientific community with state of art knowledge on their 3D structures, binding topologies and potential applications in the drug discovery field. Method:: Several databases, such as the Pfam (Protein family), the SMART (Simple Modular Architecture Research Tool) and the PDB (Protein Data Bank), were searched to look for different domain families and gain structural information on protein complexes in which particular PIDs are involved. Recent literature on PIDs and related drug discovery campaigns was retrieved through Pubmed and analyzed. Results and Conclusion:: PIDs are rather versatile as concerning their binding preferences. Many of them recognize specifically only determined amino acid stretches with post-translational modifications, a few others are able to interact with several post-translationally modified sequences or with unmodified ones. Many PIDs can be linked to different diseases including cancer. The tremendous amount of available structural data led to the structure-based design of several molecules targeting protein-protein interactions mediated by PIDs, including peptides, peptidomimetics and small compounds. More studies are needed to fully role out, among different families, PIDs that can be considered reliable therapeutic targets, however, attacking PIDs rather than catalytic domains of a particular protein may represent a route to obtain selective inhibitors.


eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Dan Tan ◽  
Qiang Li ◽  
Mei-Jun Zhang ◽  
Chao Liu ◽  
Chengying Ma ◽  
...  

To improve chemical cross-linking of proteins coupled with mass spectrometry (CXMS), we developed a lysine-targeted enrichable cross-linker containing a biotin tag for affinity purification, a chemical cleavage site to separate cross-linked peptides away from biotin after enrichment, and a spacer arm that can be labeled with stable isotopes for quantitation. By locating the flexible proteins on the surface of 70S ribosome, we show that this trifunctional cross-linker is effective at attaining structural information not easily attainable by crystallography and electron microscopy. From a crude Rrp46 immunoprecipitate, it helped identify two direct binding partners of Rrp46 and 15 protein-protein interactions (PPIs) among the co-immunoprecipitated exosome subunits. Applying it to E. coli and C. elegans lysates, we identified 3130 and 893 inter-linked lysine pairs, representing 677 and 121 PPIs. Using a quantitative CXMS workflow we demonstrate that it can reveal changes in the reactivity of lysine residues due to protein-nucleic acid interaction.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Miaomiao Bai ◽  
Dongdong Ti ◽  
Qian Mei ◽  
Jiejie Liu ◽  
Xin Yan ◽  
...  

The human body is a complex structure of cells, which are exposed to many types of stress. Cells must utilize various mechanisms to protect their DNA from damage caused by metabolic and external sources to maintain genomic integrity and homeostasis and to prevent the development of cancer. DNA damage inevitably occurs regardless of physiological or abnormal conditions. In response to DNA damage, signaling pathways are activated to repair the damaged DNA or to induce cell apoptosis. During the process, posttranslational modifications (PTMs) can be used to modulate enzymatic activities and regulate protein stability, protein localization, and protein-protein interactions. Thus, PTMs in DNA repair should be studied. In this review, we will focus on the current understanding of the phosphorylation, poly(ADP-ribosyl)ation, ubiquitination, SUMOylation, acetylation, and methylation of six typical PTMs and summarize PTMs of the key proteins in DNA repair, providing important insight into the role of PTMs in the maintenance of genome stability and contributing to reveal new and selective therapeutic approaches to target cancers.


2005 ◽  
Vol 386 (3) ◽  
pp. 401-416 ◽  
Author(s):  
Yvonne GROEMPING ◽  
Katrin RITTINGER

The NADPH oxidase of professional phagocytes is a crucial component of the innate immune response due to its fundamental role in the production of reactive oxygen species that act as powerful microbicidal agents. The activity of this multi-protein enzyme is dependent on the regulated assembly of the six enzyme subunits at the membrane where oxygen is reduced to superoxide anions. In the resting state, four of the enzyme subunits are maintained in the cytosol, either through auto-inhibitory interactions or through complex formation with accessory proteins that are not part of the active enzyme complex. Multiple inputs are required to disrupt these inhibitory interactions and allow translocation to the membrane and association with the integral membrane components. Protein interaction modules are key regulators of NADPH oxidase assembly, and the protein–protein interactions mediated via these domains have been the target of numerous studies. Many models have been put forward to describe the intricate network of reversible protein interactions that regulate the activity of this enzyme, but an all-encompassing model has so far been elusive. An important step towards an understanding of the molecular basis of NADPH oxidase assembly and activity has been the recent solution of the three-dimensional structures of some of the oxidase components. We will discuss these structures in the present review and attempt to reconcile some of the conflicting models on the basis of the structural information available.


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