We review the use of nuclear magnetic resonance(NMR)spectroscopy to assess the exchange of amide protons for deuterons(HDX)in efforts to understand how high concentration of cosolutes,especially macromolecules,affect ...We review the use of nuclear magnetic resonance(NMR)spectroscopy to assess the exchange of amide protons for deuterons(HDX)in efforts to understand how high concentration of cosolutes,especially macromolecules,affect the equilibrium thermodynamics of protein stability.HDX NMR is the only method that can routinely provide such data at the level of individual amino acids.We begin by discussing the properties of the protein systems required to yield equilibrium thermodynamic data and then review publications using osmolytes,sugars,denaturants,synthetic polymers,proteins,cytoplasm and in cells.展开更多
Macromolecular assemblies such as protein complexes and protein/RNA condensates are involved in most fundamental cellular processes.The arrangement of subunits within these nano-assemblies is critical for their biolog...Macromolecular assemblies such as protein complexes and protein/RNA condensates are involved in most fundamental cellular processes.The arrangement of subunits within these nano-assemblies is critical for their biological function and is determined by the topology of physical contacts within and between the subunits forming the complex.Describing the spatial arrangement of these interactions is of central importance to understand their functional and stability consequences.In this concept article,we propose a circuit topology-based formalism to define the topology of a complex consisting of linear polymeric chains with interand intrachain interactions.We apply our method to a system of model polymer chains as well as protein assemblies.We show that circuit topology can categorize different forms of chain assemblies.Our multi-chain circuit topology should aid analysis and predictions of mechanistic and evolutionary principles in the design of macromolecular assemblies.展开更多
It has been a dream that theoretical biology can be extensively applied in experimental biology to accelerate the understanding of the sophiscated movements in living organisms. A brave assay and an excellent example ...It has been a dream that theoretical biology can be extensively applied in experimental biology to accelerate the understanding of the sophiscated movements in living organisms. A brave assay and an excellent example were represented by enzymology, in which the well-established physico-chemistry is used to describe, to fit, to predict and to improve enzyme reactions. Before the modern bioinformatics, the developments of the combination of theoretical biology and experimental biology have been mainly limited to various classic formulations. The systematic use of graphic rules by Prof. Kuo-Chen Chou and his co-workers has significantly facilitated to deal with complicated enzyme systems. With the recent fast progress of bioinformatics, prediction of protein structures and various protein attributes have been well established by Chou and co-workers, stimulating the experimental biology. For example, their recent method for predicting protein subcellular localization (one of the important attributes of proteins) has been extensively applied by scientific colleagues, yielding many new results with thousands of citations. The research by Prof. Chou is characterized by introducing novel physical concepts as well as powerful and elegant mathematical methods into important biomedical problems, a focus throughout his career, even when facing enormous difficulties. His efforts in 50 years have greatly helped us to realize the dream to make “theoretical and experimental biology in one”. Prof. Richard Giege is well known for his multi-disciplinary research combining physics, chemistry, enzymology and molecular biology. His major focus of study is on the identity of tRNAs and their interactions with aminoacyl-tRNA synthetases (aaRS), which are of critical importance to the fidelity of protein biosynthesis. He and his colleagues have carried out the first crystallization of a tRNA/aaRS complex, that between tRNAAsp and AspRS from yeast. The determination of the complex structure contributed significantly to under- stand the展开更多
There are evidences indicating that cysteine proteases play an essential role in malaria parasites;therefore, an obvious area of investigation is the inhibition of these enzymes to treat malaria. Small cysteine protea...There are evidences indicating that cysteine proteases play an essential role in malaria parasites;therefore, an obvious area of investigation is the inhibition of these enzymes to treat malaria. Small cysteine protease inhibitors of malaria are well studied, but macromolecular nature of inhibitor is a new field to explore. In malarial cysteine proteases, there are macromolecular endogenous inhibitors playing important roles in regulation of the cysteine protease activity of parasite and host. Recent studies suggested that there are known and characterized endogenous inhibitors like falstatin present in P. falciparum, PbICP (inhibitor of cysteine protease in P. berghei), PyICP (inhibitor of cysteine protease in P. yoelli), and other macromolecular inhibitors which are the prodomain of enzyme itself regulating the activity of the mature enzyme. All the known macromolecular endogenous inhibitors are using specific loop-like structure to interact with malarial cysteine proteases. The majority of macromolecular inhibitors are competitive in nature, and block access to the active site of their target protease, but do not bind in a strictly substrate-like manner. They rather interact with the protease subsites and catalytic residues in a non-catalytically competent manner. In future, designing inhibitors based on these protein-protein interactions will be a new approach in the field of malaria. Since macromolecular inhibitors can gain potency through the burial of a large surface area and specificity through contacts with secondary binding sites critical for inhibition, and could be less prone to drug resistant mutation.展开更多
Deposition of cell wall-reinforcing papillae is an integral component of the plant immune response. TheArabidopsis PENETRATION 3 （PEN3） ATP binding cassette （ABC） transporter plays a role in defense against numero...Deposition of cell wall-reinforcing papillae is an integral component of the plant immune response. TheArabidopsis PENETRATION 3 （PEN3） ATP binding cassette （ABC） transporter plays a role in defense against numerous pathogens and is recruited to sites of pathogen detection where it accumulates within papillae. However, the trafficking pathways and regulatory mechanisms contributing to recruitment of PEN3 and other defenses to the host-pathogen interface are poorly understood. Here, we report a confocal microscopy-based screen to identify mutants with altered localization of PEN3-GFP after inoculation with powdery mildew fungi. We identified a mutant, aberrant localization of PEN3 3 （alp3）, displaying accumulation of the normally plasma membrane （PM）-Iocalized PEN3-GFP in endomembrane compartments. The mutant was found to be disrupted in the P4-ATPase AMINOPHOSPHOLIPID ATPASE 3 （ALA3）, a lipid flippase that plays a critical role in vesicle formation. We provide evidence that PEN3 undergoes continuous endocytic cycling from the PM to the trans-Golgi network （TGN）. In alp3, PEN3 accumulates in the TGN, causing delays in recruitment to the host-pathogen interface. Our results indicate that PEN3 and other defense proteins continuously cycle through the TGN and that timely exit of these proteins from the TGN is critical for effective pre-invasive immune responses against powdery mildews.展开更多
文摘We review the use of nuclear magnetic resonance(NMR)spectroscopy to assess the exchange of amide protons for deuterons(HDX)in efforts to understand how high concentration of cosolutes,especially macromolecules,affect the equilibrium thermodynamics of protein stability.HDX NMR is the only method that can routinely provide such data at the level of individual amino acids.We begin by discussing the properties of the protein systems required to yield equilibrium thermodynamic data and then review publications using osmolytes,sugars,denaturants,synthetic polymers,proteins,cytoplasm and in cells.
文摘Macromolecular assemblies such as protein complexes and protein/RNA condensates are involved in most fundamental cellular processes.The arrangement of subunits within these nano-assemblies is critical for their biological function and is determined by the topology of physical contacts within and between the subunits forming the complex.Describing the spatial arrangement of these interactions is of central importance to understand their functional and stability consequences.In this concept article,we propose a circuit topology-based formalism to define the topology of a complex consisting of linear polymeric chains with interand intrachain interactions.We apply our method to a system of model polymer chains as well as protein assemblies.We show that circuit topology can categorize different forms of chain assemblies.Our multi-chain circuit topology should aid analysis and predictions of mechanistic and evolutionary principles in the design of macromolecular assemblies.
文摘It has been a dream that theoretical biology can be extensively applied in experimental biology to accelerate the understanding of the sophiscated movements in living organisms. A brave assay and an excellent example were represented by enzymology, in which the well-established physico-chemistry is used to describe, to fit, to predict and to improve enzyme reactions. Before the modern bioinformatics, the developments of the combination of theoretical biology and experimental biology have been mainly limited to various classic formulations. The systematic use of graphic rules by Prof. Kuo-Chen Chou and his co-workers has significantly facilitated to deal with complicated enzyme systems. With the recent fast progress of bioinformatics, prediction of protein structures and various protein attributes have been well established by Chou and co-workers, stimulating the experimental biology. For example, their recent method for predicting protein subcellular localization (one of the important attributes of proteins) has been extensively applied by scientific colleagues, yielding many new results with thousands of citations. The research by Prof. Chou is characterized by introducing novel physical concepts as well as powerful and elegant mathematical methods into important biomedical problems, a focus throughout his career, even when facing enormous difficulties. His efforts in 50 years have greatly helped us to realize the dream to make “theoretical and experimental biology in one”. Prof. Richard Giege is well known for his multi-disciplinary research combining physics, chemistry, enzymology and molecular biology. His major focus of study is on the identity of tRNAs and their interactions with aminoacyl-tRNA synthetases (aaRS), which are of critical importance to the fidelity of protein biosynthesis. He and his colleagues have carried out the first crystallization of a tRNA/aaRS complex, that between tRNAAsp and AspRS from yeast. The determination of the complex structure contributed significantly to under- stand the
文摘There are evidences indicating that cysteine proteases play an essential role in malaria parasites;therefore, an obvious area of investigation is the inhibition of these enzymes to treat malaria. Small cysteine protease inhibitors of malaria are well studied, but macromolecular nature of inhibitor is a new field to explore. In malarial cysteine proteases, there are macromolecular endogenous inhibitors playing important roles in regulation of the cysteine protease activity of parasite and host. Recent studies suggested that there are known and characterized endogenous inhibitors like falstatin present in P. falciparum, PbICP (inhibitor of cysteine protease in P. berghei), PyICP (inhibitor of cysteine protease in P. yoelli), and other macromolecular inhibitors which are the prodomain of enzyme itself regulating the activity of the mature enzyme. All the known macromolecular endogenous inhibitors are using specific loop-like structure to interact with malarial cysteine proteases. The majority of macromolecular inhibitors are competitive in nature, and block access to the active site of their target protease, but do not bind in a strictly substrate-like manner. They rather interact with the protease subsites and catalytic residues in a non-catalytically competent manner. In future, designing inhibitors based on these protein-protein interactions will be a new approach in the field of malaria. Since macromolecular inhibitors can gain potency through the burial of a large surface area and specificity through contacts with secondary binding sites critical for inhibition, and could be less prone to drug resistant mutation.
基金This research was supported, in part, by National Science Foundation Grants 0519898 and 0929226 and startup funds to S.C.S., and by NIH Postdoctoral Fellowship F32-GM-0834393 and funding from the USDA Agricultural Research Service to W.U. This work used the Vincent J. Coates Genomics Sequencing Laboratory at UC Berkeley, supported by NIH S10 instrumentation Grants S10RR029668 and S10RR027303. USDA is an equal opportunity provider and employer.
文摘Deposition of cell wall-reinforcing papillae is an integral component of the plant immune response. TheArabidopsis PENETRATION 3 （PEN3） ATP binding cassette （ABC） transporter plays a role in defense against numerous pathogens and is recruited to sites of pathogen detection where it accumulates within papillae. However, the trafficking pathways and regulatory mechanisms contributing to recruitment of PEN3 and other defenses to the host-pathogen interface are poorly understood. Here, we report a confocal microscopy-based screen to identify mutants with altered localization of PEN3-GFP after inoculation with powdery mildew fungi. We identified a mutant, aberrant localization of PEN3 3 （alp3）, displaying accumulation of the normally plasma membrane （PM）-Iocalized PEN3-GFP in endomembrane compartments. The mutant was found to be disrupted in the P4-ATPase AMINOPHOSPHOLIPID ATPASE 3 （ALA3）, a lipid flippase that plays a critical role in vesicle formation. We provide evidence that PEN3 undergoes continuous endocytic cycling from the PM to the trans-Golgi network （TGN）. In alp3, PEN3 accumulates in the TGN, causing delays in recruitment to the host-pathogen interface. Our results indicate that PEN3 and other defense proteins continuously cycle through the TGN and that timely exit of these proteins from the TGN is critical for effective pre-invasive immune responses against powdery mildews.
