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Full-Text Articles in Medicine and Health Sciences
Denaturation And Unfolding Of Human Anaphylatoxin C3a: An Unusually Low Covalent Stability Of Its Native Disulfide Bonds, Jui-Yoa Chang, Curtis C-J Lin, Silvia Salamanca, Michael K Pangburn, Rick A Wetsel
Denaturation And Unfolding Of Human Anaphylatoxin C3a: An Unusually Low Covalent Stability Of Its Native Disulfide Bonds, Jui-Yoa Chang, Curtis C-J Lin, Silvia Salamanca, Michael K Pangburn, Rick A Wetsel
Journal Articles
The complement C3a anaphylatoxin is a major molecular mediator of innate immunity. It is a potent activator of mast cells, basophils and eosinophils and causes smooth muscle contraction. Structurally, C3a is a relatively small protein (77 amino acids) comprising a N-terminal domain connected by 3 native disulfide bonds and a helical C-terminal segment. The structural stability of C3a has been investigated here using three different methods: Disulfide scrambling; Differential CD spectroscopy; and Reductive unfolding. Two uncommon features regarding the stability of C3a and the structure of denatured C3a have been observed in this study. (a) There is an unusual disconnection …
Role Of The N- And C-Lobes Of Calmodulin In The Activation Of Ca(2+)/Calmodulin-Dependent Protein Kinase Ii, Amelie Forest, Matthew T Swulius, Joyce K Y Tse, J Michael Bradshaw, Tara Gaertner, M Neal Waxham
Role Of The N- And C-Lobes Of Calmodulin In The Activation Of Ca(2+)/Calmodulin-Dependent Protein Kinase Ii, Amelie Forest, Matthew T Swulius, Joyce K Y Tse, J Michael Bradshaw, Tara Gaertner, M Neal Waxham
Journal Articles
Understanding the principles of calmodulin (CaM) activation of target enzymes will help delineate how this seemingly simple molecule can play such a complex role in transducing Ca (2+)-signals to a variety of downstream pathways. In the work reported here, we use biochemical and biophysical tools and a panel of CaM constructs to examine the lobe specific interactions between CaM and CaMKII necessary for the activation and autophosphorylation of the enzyme. Interestingly, the N-terminal lobe of CaM by itself was able to partially activate and allow autophosphorylation of CaMKII while the C-terminal lobe was inactive. When used together, CaMN and CaMC …
Subnanometer-Resolution Structures Of The Grass Carp Reovirus Core And Virion, Lingpeng Cheng, Qin Fang, Sanket Shah, Ivo C Atanasov, Z Hong Zhou
Subnanometer-Resolution Structures Of The Grass Carp Reovirus Core And Virion, Lingpeng Cheng, Qin Fang, Sanket Shah, Ivo C Atanasov, Z Hong Zhou
Journal Articles
Grass carp reovirus (GCRV) is a member of the Aquareovirus genus of the family Reoviridae, a large family of double-stranded RNA (dsRNA) viruses infecting plants, insects, fishes and mammals. We report the first subnanometer-resolution three-dimensional structures of both GCRV core and virion by cryoelectron microscopy. These structures have allowed the delineation of interactions among the over 1000 molecules in this enormous macromolecular machine and a detailed comparison with other dsRNA viruses at the secondary-structure level. The GCRV core structure shows that the inner proteins have strong structural similarities with those of orthoreoviruses even at the level of secondary-structure elements, indicating …
Structure Of The Hsp110:Hsc70 Nucleotide Exchange Machine, Jonathan P Schuermann, Jianwen Jiang, Jorge Cuellar, Oscar Llorca, Liping Wang, Luis E Gimenez, Suping Jin, Alexander B Taylor, Borries Demeler, Kevin A Morano, P John Hart, Jose M Valpuesta, Eileen M Lafer, Rui Sousa
Structure Of The Hsp110:Hsc70 Nucleotide Exchange Machine, Jonathan P Schuermann, Jianwen Jiang, Jorge Cuellar, Oscar Llorca, Liping Wang, Luis E Gimenez, Suping Jin, Alexander B Taylor, Borries Demeler, Kevin A Morano, P John Hart, Jose M Valpuesta, Eileen M Lafer, Rui Sousa
Journal Articles
Hsp70s mediate protein folding, translocation, and macromolecular complex remodeling reactions. Their activities are regulated by proteins that exchange ADP for ATP from the nucleotide-binding domain (NBD) of the Hsp70. These nucleotide exchange factors (NEFs) include the Hsp110s, which are themselves members of the Hsp70 family. We report the structure of an Hsp110:Hsc70 nucleotide exchange complex. The complex is characterized by extensive protein:protein interactions and symmetric bridging interactions between the nucleotides bound in each partner protein's NBD. An electropositive pore allows nucleotides to enter and exit the complex. The role of nucleotides in complex formation and dissociation, and the effects of …
388 A Structure Of Cytoplasmic Polyhedrosis Virus By Cryo-Electron Microscopy, Xuekui Yu, Lei Jin, Z Hong Zhou
388 A Structure Of Cytoplasmic Polyhedrosis Virus By Cryo-Electron Microscopy, Xuekui Yu, Lei Jin, Z Hong Zhou
Journal Articles
Cytoplasmic polyhedrosis virus (CPV) is unique within the Reoviridae family in having a turreted single-layer capsid contained within polyhedrin inclusion bodies, yet being fully capable of cell entry and endogenous RNA transcription. Biochemical data have shown that the amino-terminal 79 residues of the CPV turret protein (TP) is sufficient to bring CPV or engineered proteins into the polyhedrin matrix for micro-encapsulation. Here we report the three-dimensional structure of CPV at 3.88 A resolution using single-particle cryo-electron microscopy. Our map clearly shows the turns and deep grooves of alpha-helices, the strand separation in beta-sheets, and densities for loops and many bulky …
Unique Structures In A Tumor Herpesvirus Revealed By Cryo-Electron Tomography And Microscopy, Wei Dai, Qingmei Jia, Eric Bortz, Sanket Shah, Jun Liu, Ivo Atanasov, Xudong Li, Kenneth A Taylor, Ren Sun, Z Hong Zhou
Unique Structures In A Tumor Herpesvirus Revealed By Cryo-Electron Tomography And Microscopy, Wei Dai, Qingmei Jia, Eric Bortz, Sanket Shah, Jun Liu, Ivo Atanasov, Xudong Li, Kenneth A Taylor, Ren Sun, Z Hong Zhou
Journal Articles
Gammaherpesviruses, including the human pathogens Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus, are causative agents of lymphomas and other malignancies. The structural characterization of these viruses has been limited due to difficulties in obtaining adequate amount of virion particles. Here we report the first three-dimensional structural characterization of a whole gammaherpesvirus virion by an emerging integrated approach of cryo-electron tomography combined with single-particle cryo-electron microscopy, using murine gammaherpesvirus-68 (MHV-68) as a model system. We found that the MHV-68 virion consists of distinctive envelope and tegument compartments, and a highly conserved nucleocapsid. Two layers of tegument are identified: an inner tegument layer …