Crystal structure of a cAMP-independent form of catabolite gene activator protein with adenosine substituted in one of two cAMP-binding sites

Biochemistry ◽  
1989 ◽  
Vol 28 (11) ◽  
pp. 4568-4574 ◽  
Author(s):  
Marie Christine Vaney ◽  
Gary L. Gilliland ◽  
James G. Harman ◽  
Alan Peterkofsky ◽  
Irene T. Weber
Keyword(s):  
Crystal Structure ◽  
Binding Sites ◽  
Activator Protein ◽  
Independent Form ◽  
Catabolite Gene Activator Protein

scholarly journals Crystal structures of Ca2+–calmodulin bound to NaV C-terminal regions suggest role for EF-hand domain in binding and inactivation

2019 ◽  
Vol 116 (22) ◽  
pp. 10763-10772 ◽  
Author(s):  
Bernd R. Gardill ◽  
Ricardo E. Rivera-Acevedo ◽  
Ching-Chieh Tung ◽  
Filip Van Petegem
Keyword(s):  
Crystal Structure ◽  
Binding Sites ◽  
Binding Mode ◽  
Conformational Switch ◽  
Channel Inactivation ◽  
Dependent Inactivation ◽  
Ef Hand ◽  
Inherited Arrhythmia ◽  
A Site

Voltage-gated sodium (NaV) and calcium channels (CaV) form targets for calmodulin (CaM), which affects channel inactivation properties. A major interaction site for CaM resides in the C-terminal (CT) region, consisting of an IQ domain downstream of an EF-hand domain. We present a crystal structure of fully Ca2+-occupied CaM, bound to the CT of NaV1.5. The structure shows that the C-terminal lobe binds to a site ∼90° rotated relative to a previous site reported for an apoCaM complex with the NaV1.5 CT and for ternary complexes containing fibroblast growth factor homologous factors (FHF). We show that the binding of FHFs forces the EF-hand domain in a conformation that does not allow binding of the Ca2+-occupied C-lobe of CaM. These observations highlight the central role of the EF-hand domain in modulating the binding mode of CaM. The binding sites for Ca2+-free and Ca2+-occupied CaM contain targets for mutations linked to long-QT syndrome, a type of inherited arrhythmia. The related NaV1.4 channel has been shown to undergo Ca2+-dependent inactivation (CDI) akin to CaVs. We present a crystal structure of Ca2+/CaM bound to the NaV1.4 IQ domain, which shows a binding mode that would clash with the EF-hand domain. We postulate the relative reorientation of the EF-hand domain and the IQ domain as a possible conformational switch that underlies CDI.

Crystal structure of the C-terminal domain of envelope protein VP37 from white spot syndrome virus reveals sulphate binding sites responsible for heparin binding

2021 ◽  
Vol 102 (6) ◽  
Author(s):  
Wasusit Somsoros ◽  
Takeshi Sangawa ◽  
Katsuki Takebe ◽  
Jakrada Attarataya ◽  
Kanokpan Wongprasert ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Binding Sites ◽  
Envelope Protein ◽  
Molecular Mechanisms ◽  
White Spot Syndrome Virus ◽  
Significant Loss ◽  
White Spot ◽  
Heparin Binding ◽  
Terminal Domain ◽  
White Spot Syndrome

White spot syndrome virus (WSSV) is the most virulent pathogen causing high mortality and economic loss in shrimp aquaculture and various crustaceans. Therefore, the understanding of molecular mechanisms of WSSV infection is important to develop effective therapeutics to control the spread of this viral disease. In a previous study, we found that VP37 could bind with shrimp haemocytes through the interaction between its C-terminal domain and heparin-like molecules on the shrimp cells, and this interaction can also be inhibited by sulphated galactan. In this study, we present the crystal structure of C-terminal domain of VP37 from WSSV at a resolution of 2.51 Å. The crystal structure contains an eight-stranded β-barrel fold with an antiparallel arrangement and reveals a trimeric assembly. Moreover, there are two sulphate binding sites found in the position corresponding to R213 and K257. In order to determine whether these sulphate binding sites are involved in binding of VP37 to heparin, mutagenesis was performed to replace these residues with alanine (R213A and K257A), and the Surface Plasmon Resonance (SPR) system was used to study the interaction of each mutated VP37 with heparin. The results showed that mutants R213A and K257A exhibited a significant loss in heparin binding activity. These findings indicated that the sites of R213 and K257 on the C-terminal domain of envelope protein VP37 are essential for binding to sulphate molecules of heparin. This study provides further insight into the structure of C-terminal domain of VP37 and it is anticipated that the structure of VP37 might be used as a guideline for development of antivirus agent targeting on the VP37 protein.

Sign in / Sign up

Export Citation Format

Share Document