scholarly journals Ritonavir and xk263 Binding-Unbinding with HIV-1 Protease: Pathways, Energy and Comparison

Life ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 116
Author(s):  
Jianan Sun ◽  
Mark Anthony V. Raymundo ◽  
Chia-En A. Chang
Keyword(s):  
Protein Interactions ◽  
Bound States ◽  
Binding Pocket ◽  
Specific Protein ◽  
Hiv Protease ◽  
Accelerated Molecular Dynamics ◽  
Solvent Model ◽  
Integral Role ◽  
Explicit Solvent Model ◽  
Key Residues

Understanding non-covalent biomolecular recognition, which includes drug–protein bound states and their binding/unbinding processes, is of fundamental importance in chemistry, biology, and medicine. Fully revealing the factors that govern the binding/unbinding processes can further assist in designing drugs with desired binding kinetics. HIV protease (HIVp) plays an integral role in the HIV life cycle, so it is a prime target for drug therapy. HIVp has flexible flaps, and the binding pocket can be accessible by a ligand via various pathways. Comparing ligand association and dissociation pathways can help elucidate the ligand–protein interactions such as key residues directly involved in the interaction or specific protein conformations that determine the binding of a ligand under certain pathway(s). Here, we investigated the ligand unbinding process for a slow binder, ritonavir, and a fast binder, xk263, by using unbiased all-atom accelerated molecular dynamics (aMD) simulation with a re-seeding approach and an explicit solvent model. Using ritonavir-HIVp and xk263-HIVp ligand–protein systems as cases, we sampled multiple unbinding pathways for each ligand and observed that the two ligands preferred the same unbinding route. However, ritonavir required a greater HIVp motion to dissociate as compared with xk263, which can leave the binding pocket with little conformational change of HIVp. We also observed that ritonavir unbinding pathways involved residues which are associated with drug resistance and are distal from catalytic site. Analyzing HIVp conformations sampled during both ligand–protein binding and unbinding processes revealed significantly more overlapping HIVp conformations for ritonavir-HIVp rather than xk263-HIVp. However, many HIVp conformations are unique in xk263-HIVp unbinding processes. The findings are consistent with previous findings that xk263 prefers an induced-fit model for binding and unbinding, whereas ritonavir favors a conformation selection model. This study deepens our understanding of the dynamic process of ligand unbinding and provides insights into ligand–protein recognition mechanisms and drug discovery.

scholarly journals Cryo-EM structure of the human histamine H1 receptor/Gq complex

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ruixue Xia ◽  
Na Wang ◽  
Zhenmei Xu ◽  
Yang Lu ◽  
Jing Song ◽  
...  
Keyword(s):  
Transmembrane Domain ◽  
Binding Pocket ◽  
Receptor Activation ◽  
Intracellular Loop ◽  
Cryo Electron Microscopy ◽  
Allergy Treatment ◽  
Domain 3 ◽  
Extracellular Side ◽  
Key Residues ◽  
Loop 2

AbstractHistamine receptors play important roles in various pathophysiological conditions and are effective targets for anti-allergy treatment, however the mechanism of receptor activation remain elusive. Here, we present the cryo-electron microscopy (cryo-EM) structure of the human H1R in complex with a Gq protein in an active conformation via a NanoBiT tethering strategy. The structure reveals that histamine activates receptor via interacting with the key residues of both transmembrane domain 3 (TM3) and TM6 to squash the binding pocket on the extracellular side and to open the cavity on the intracellular side for Gq engagement in a model of “squash to activate and expand to deactivate”. The structure also reveals features for Gq coupling, including the interaction between intracellular loop 2 (ICL2) and the αN-β junction of Gq/11 protein. The detailed analysis of our structure will provide a framework for understanding G-protein coupling selectivity and clues for designing novel antihistamines.

Structure, Function, Involvement in Diseases and Targeting of 14-3-3 Proteins: An Update

2018 ◽  
Vol 25 (1) ◽  
pp. 5-21 ◽  
Author(s):  
Ylenia Cau ◽  
Daniela Valensin ◽  
Mattia Mori ◽  
Sara Draghi ◽  
Maurizio Botta
Keyword(s):  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Physiological Role ◽  
Specific Protein ◽  
Protein Protein Interactions ◽  
Cellular Processes ◽  
Protein Partners ◽  
High Sequence Homology ◽  
Small Molecule Modulators

14-3-3 is a class of proteins able to interact with a multitude of targets by establishing protein-protein interactions (PPIs). They are usually found in all eukaryotes with a conserved secondary structure and high sequence homology among species. 14-3-3 proteins are involved in many physiological and pathological cellular processes either by triggering or interfering with the activity of specific protein partners. In the last years, the scientific community has collected many evidences on the role played by seven human 14-3-3 isoforms in cancer or neurodegenerative diseases. Indeed, these proteins regulate the molecular mechanisms associated to these diseases by interacting with (i) oncogenic and (ii) pro-apoptotic proteins and (iii) with proteins involved in Parkinson and Alzheimer diseases. The discovery of small molecule modulators of 14-3-3 PPIs could facilitate complete understanding of the physiological role of these proteins, and might offer valuable therapeutic approaches for these critical pathological states.

scholarly journals Novel Roles of SH2 and SH3 Domains in Lipid Binding

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1191
Author(s):  
Szabolcs Sipeki ◽  
Kitti Koprivanacz ◽  
Tamás Takács ◽  
Anita Kurilla ◽  
Loretta László ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Specific Protein ◽  
Lipid Binding ◽  
Sh2 Domain ◽  
Essential Property ◽  
Cellular Regulation ◽  
Sh3 Domains ◽  
Protein Partners ◽  
Interaction Domains ◽  
Central Paradigm

Signal transduction, the ability of cells to perceive information from the surroundings and alter behavior in response, is an essential property of life. Studies on tyrosine kinase action fundamentally changed our concept of cellular regulation. The induced assembly of subcellular hubs via the recognition of local protein or lipid modifications by modular protein interactions is now a central paradigm in signaling. Such molecular interactions are mediated by specific protein interaction domains. The first such domain identified was the SH2 domain, which was postulated to be a reader capable of finding and binding protein partners displaying phosphorylated tyrosine side chains. The SH3 domain was found to be involved in the formation of stable protein sub-complexes by constitutively attaching to proline-rich surfaces on its binding partners. The SH2 and SH3 domains have thus served as the prototypes for a diverse collection of interaction domains that recognize not only proteins but also lipids, nucleic acids, and small molecules. It has also been found that particular SH2 and SH3 domains themselves might also bind to and rely on lipids to modulate complex assembly. Some lipid-binding properties of SH2 and SH3 domains are reviewed here.

Genetic regulation of nitrogen metabolism in the fungi

1997 ◽  
Vol 61 (1) ◽  
pp. 17-32
Author(s):  
G A Marzluf
Keyword(s):  
Nitrogen Metabolism ◽  
Protein Interactions ◽  
Fungal Pathogens ◽  
Metabolic Regulation ◽  
Specific Binding ◽  
Genetic Regulation ◽  
Nitrogen Sources ◽  
Specific Protein ◽  
Genes Encoding ◽  
Gata Family

In the fungi, nitrogen metabolism is controlled by a complex genetic regulatory circuit which ensures the preferential use of primary nitrogen sources and also confers the ability to use many different secondary nitrogen sources when appropriate. Most structural genes encoding nitrogen catabolic enzymes are subject to nitrogen catabolite repression, mediated by positive-acting transcription factors of the GATA family of proteins. However, certain GATA family members, such as the yeast DAL80 factor, act negatively to repress gene expression. Selective expression of the genes which encode enzymes for the metabolism of secondary nitrogen sources is often achieved by induction, mediated by pathway-specific factors, many of which have a GAL4-like C6/Zn2 DNA binding domain. Regulation within the nitrogen circuit also involves specific protein-protein interactions, as exemplified by the specific binding of the negative-acting NMR protein with the positive-acting NIT2 protein of Neurospora crassa. Nitrogen metabolic regulation appears to play a significant role in the pathogenicity of certain animal and plant fungal pathogens.

scholarly journals WWOXgene and gene product: tumor suppression through specific protein interactions

2010 ◽  
Vol 6 (2) ◽  
pp. 249-259 ◽  
Author(s):  
Zaidoun Salah ◽  
Rami Aqeilan ◽  
Kay Huebner
Keyword(s):  
Gene Product ◽  
Protein Interactions ◽  
Tumor Suppression ◽  
Specific Protein

scholarly journals Allostery revealed within lipid binding events to membrane proteins

2018 ◽  
Vol 115 (12) ◽  
pp. 2976-2981 ◽  
Author(s):  
John W. Patrick ◽  
Christopher D. Boone ◽  
Wen Liu ◽  
Gloria M. Conover ◽  
Yang Liu ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Protein Interactions ◽  
Biological Membrane ◽  
Binding Constants ◽  
Native Mass Spectrometry ◽  
Specific Protein ◽  
Lipid Binding ◽  
Allosteric Modulation ◽  
Lipid Species ◽  
Specific Lipid

Membrane proteins interact with a myriad of lipid species in the biological membrane, leading to a bewildering number of possible protein−lipid assemblies. Despite this inherent complexity, the identification of specific protein−lipid interactions and the crucial role of lipids in the folding, structure, and function of membrane proteins is emerging from an increasing number of reports. Fundamental questions remain, however, regarding the ability of specific lipid binding events to membrane proteins to alter remote binding sites for lipids of a different type, a property referred to as allostery [Monod J, Wyman J, Changeux JP (1965)J Mol Biol12:88–118]. Here, we use native mass spectrometry to determine the allosteric nature of heterogeneous lipid binding events to membrane proteins. We monitored individual lipid binding events to the ammonia channel (AmtB) fromEscherichia coli, enabling determination of their equilibrium binding constants. We found that different lipid pairs display a range of allosteric modulation. In particular, the binding of phosphatidylethanolamine and cardiolipin-like molecules to AmtB exhibited the largest degree of allosteric modulation, inspiring us to determine the cocrystal structure of AmtB in this lipid environment. The 2.45-Å resolution structure reveals a cardiolipin-like molecule bound to each subunit of the trimeric complex. Mutation of a single residue in AmtB abolishes the positive allosteric modulation observed for binding phosphatidylethanolamine and cardiolipin-like molecules. Our results demonstrate that specific lipid−protein interactions can act as allosteric modulators for the binding of different lipid types to integral membrane proteins.

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