Structural basis of the ultrasensitive calcium indicator GCaMP6

GCaMP is one of the most widely used calcium indicators in neuronal imaging and calcium cell biology. The newly developed GCaMP6 shows superior brightness and ultrasensitivity to calcium concentration change. In this study, we determined crystal structures of CaZ＋-bound GCaMP6 monomer and dimer and presented detailed structural analyses in comparison with its par- ent version GCaMP5G. Our analyses reveal the structural basis for the outperformance of this newly developed Ca2＋ indicator. Three substitution mutations and the resulting changes of local structure and interaction explain the ultrasensitivity and in- creased fluorescence intensity common to all three versions of GCaMP6. Each particular substitution in the three GCaMP6 is also structurally consistent with their differential sensitivity and intensity, maximizing the potential of using GCaMP6 in solving diverse problems in neuronal research and calcium signaling. Our studies shall also be beneficial to further structure-guided optimization of GCaMP and facilitate the design of novel calcium indicators.

The Research of Ecological Nutritional Organs of Invasive Plants Structural Characteristics

[Objective] The aim of this paper was to discuss the adaptability of ecological nutritional organs of invasive plants.[Method] By dint of high-definition display of plant tissue crystal method and paraffin section method,the vegetative organs root,stem and leaf cross-section of the organizational structure of Asteraceae Ambrosia trifida L.ragweed（Ambrosia trifida L.）in the suburbs of Changchun City in Jilin Province were inspected.[Result] The structural basis for ecological invasive plant Ambrosia trifida L.vegetative organs was mainly through strengthening the roots of water absorption and transporting function,increasing the water storage function of leaf and stem,reducing the water absorption of stem and leaf for plants to promote water absorption and to enhance the assimilation of leaves to achieve a variety of complex environmental conditions in the rapid growth and development in order to achieve an ecological invasion.[Conclusion] The study provided reference for the biological fundamental research of Ambrosia trifida L.

An efficient technique for recovering responses of parameterized structural dynamic problems

In this article,an effective technique is developed to efficiently obtain the output responses of parameterized structural dynamic problems.This technique is based on the conception of reduced basis method and the usage of linear interpolation principle.The original problem is projected onto the reduced basis space by linear interpolation projection,and subsequently an associated interpolation matrix is generated.To ensure the largest nonsingularity,the interpolation matrix needs to go through a timenode choosing process,which is developed by applying the angle of vector spaces.As a part of this technique,error estimation is recommended for achieving the computational error bound.To ensure the successful performance of this technique,the offline-online computational procedures are conducted in practical engineering.Two numerical examples demonstrate the accuracy and efficiency of the presented method.

High-resolution 3D Structures Reveal the Biological Functions of Reoviruses

Viruses in the family Reoviridae are non-enveloped particles comprising a segmented double-stranded RNA genome surrounded by a two-layered or multi-layered icosahedral protein capsid.These viruses are classified into two sub-families based on their particle structural organization.Recent studies have focused on high-resolution three-dimensional structures of reovirus particles by using cryo-electron microscopy (cryo-EM) to approach the resolutions seen in X-ray crystallographic structures.The results of cryo-EM image reconstructions allow tracing of most of the protein side chains,and thus permit integration of structural and functional information into a coherent mechanism for reovirus assembly and entry.

Oligomerization of drug transporters:Forms,functions,and mechanisms

Drug transporters are essential players in the transmembrane transport of a wide variety of clinical drugs.The broad substrate spectra and versatile distribution pattern of these membrane proteins infer their pharmacological and clinical significance.With our accumulating knowledge on the three-dimensional structure of drug transporters,their oligomerization status has become a topic of intense study due to the possible functional roles carried out by such kind of post-translational modification(PTM).In-depth studies of oligomeric complexes formed among drug transporters as well as their interactions with other regulatory proteins can help us better understand the regulatory mechanisms of these membrane proteins,provide clues for the development of novel drugs,and improve the therapeutic efficacy.In this review,we describe different oligomerization forms as well as their structural basis of major drug transporters in the ATP-binding cassette and solute carrier superfamilies,summarize our current knowledge on the influence of oligomerization for protein expression level and transport function of these membrane proteins,and discuss the regulatory mechanisms of oligomerization.Finally,we highlight the challenges associated with the current oligomerization studies and propose some thoughts on the pharmaceutical application of this important drug transporter PTM.