scholarly journals Residue Cluster Classes: A Unified Protein Representation for Efficient Structural and Functional Classification

Entropy ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 472 ◽  
Author(s):  
Fernando Fontove ◽  
Gabriel Del Rio
Keyword(s):  
Protein Structure ◽  
Three Dimensional ◽  
Side Chain ◽  
Amino Acid Side Chain ◽  
Computationally Efficient ◽  
Residue Contact ◽  
Contact Maps ◽  
Effective Models ◽  
And Function ◽  
Potential Use

Proteins are characterized by their structures and functions, and these two fundamental aspects of proteins are assumed to be related. To model such a relationship, a single representation to model both protein structure and function would be convenient, yet so far, the most effective models for protein structure or function classification do not rely on the same protein representation. Here we provide a computationally efficient implementation for large datasets to calculate residue cluster classes (RCCs) from protein three-dimensional structures and show that such representations enable a random forest algorithm to effectively learn the structural and functional classifications of proteins, according to the CATH and Gene Ontology criteria, respectively. RCCs are derived from residue contact maps built from different distance criteria, and we show that 7 or 8 Å with or without amino acid side-chain atoms rendered the best classification models. The potential use of a unified representation of proteins is discussed and possible future areas for improvement and exploration are presented.

Mutational studies of protein structures and their stabilities

1992 ◽  
Vol 25 (2) ◽  
pp. 205-250 ◽  
Author(s):  
David Shortle
Keyword(s):  
Amino Acid ◽  
Functional Role ◽  
Hydrophobic Interactions ◽  
Protein Structures ◽  
Three Dimensional ◽  
Rnase A ◽  
Side Chain ◽  
Amino Acid Side Chain ◽  
X Ray Crystallography ◽  
And Function

The fundamental relationship between structure and function has served to guide investigations into the workings of living systems at all levels - from the whole organism to individual cells on down to individual molecules. When X-ray crystallography began to reveal the three-dimensional structures of proteins like myoglobin, lysozyme and RNase A, protein chemists were well prepared to draw inferences about functional mechanisms from the precise positioning of amino acid residues they could see. The close proximity between an amino acid side chain and a chemical group on a bound ligand strongly suggests a functional role for that side chain in binding affinity and specificity. Likewise, the nearly universal finding of large clusters of hydrophobic side chains buried in the core of proteins strongly supports a major functional role of hydrophobic interactions in protein folding and stability. Even though eminently plausible hypotheses like these, grounded in the most fundamental principles of chemistry and the logic of structure–function relationships, become widely accepted and make their way into textbooks, protein chemists have felt compelled to search for ways to test them and put them on a more quantitative basis.

scholarly journals FASPR: an open-source tool for fast and accurate protein side-chain packing

2020 ◽  
Vol 36 (12) ◽  
pp. 3758-3765 ◽  
Author(s):  
Xiaoqiang Huang ◽  
Robin Pearce ◽  
Yang Zhang
Keyword(s):  
Protein Structure ◽  
Protein Design ◽  
Structure Prediction ◽  
Protein Structures ◽  
Scoring Function ◽  
Supplementary Information ◽  
Side Chain ◽  
Chain Packing ◽  
And Function ◽  
Side Chain Packing

Abstract Motivation Protein structure and function are essentially determined by how the side-chain atoms interact with each other. Thus, accurate protein side-chain packing (PSCP) is a critical step toward protein structure prediction and protein design. Despite the importance of the problem, however, the accuracy and speed of current PSCP programs are still not satisfactory. Results We present FASPR for fast and accurate PSCP by using an optimized scoring function in combination with a deterministic searching algorithm. The performance of FASPR was compared with four state-of-the-art PSCP methods (CISRR, RASP, SCATD and SCWRL4) on both native and non-native protein backbones. For the assessment on native backbones, FASPR achieved a good performance by correctly predicting 69.1% of all the side-chain dihedral angles using a stringent tolerance criterion of 20°, compared favorably with SCWRL4, CISRR, RASP and SCATD which successfully predicted 68.8%, 68.6%, 67.8% and 61.7%, respectively. Additionally, FASPR achieved the highest speed for packing the 379 test protein structures in only 34.3 s, which was significantly faster than the control methods. For the assessment on non-native backbones, FASPR showed an equivalent or better performance on I-TASSER predicted backbones and the backbones perturbed from experimental structures. Detailed analyses showed that the major advantage of FASPR lies in the optimal combination of the dead-end elimination and tree decomposition with a well optimized scoring function, which makes FASPR of practical use for both protein structure modeling and protein design studies. Availability and implementation The web server, source code and datasets are freely available at https://zhanglab.ccmb.med.umich.edu/FASPR and https://github.com/tommyhuangthu/FASPR. Supplementary information Supplementary data are available at Bioinformatics online.

scholarly journals Posttranslational modifications in proteins: resources, tools and prediction methods

Database ◽  
2021 ◽  
Author(s):  
Shahin Ramazi ◽  
Javad Zahiri
Keyword(s):  
Computational Methods ◽  
Posttranslational Modifications ◽  
Side Chain ◽  
Amino Acid Side Chain ◽  
Cellular Processes ◽  
Online Databases ◽  
Different Types ◽  
Protein Functions ◽  
And Function ◽  
Molecular Regulatory Mechanisms

Abstract Posttranslational modifications (PTMs) refer to amino acid side chain modification in some proteins after their biosynthesis. There are more than 400 different types of PTMs affecting many aspects of protein functions. Such modifications happen as crucial molecular regulatory mechanisms to regulate diverse cellular processes. These processes have a significant impact on the structure and function of proteins. Disruption in PTMs can lead to the dysfunction of vital biological processes and hence to various diseases. High-throughput experimental methods for discovery of PTMs are very laborious and time-consuming. Therefore, there is an urgent need for computational methods and powerful tools to predict PTMs. There are vast amounts of PTMs data, which are publicly accessible through many online databases. In this survey, we comprehensively reviewed the major online databases and related tools. The current challenges of computational methods were reviewed in detail as well.

PlaneFinder: a methodology to find the best plane for a set of atoms involved in the metal coordination in protein structures

2018 ◽  
Vol 51 (4) ◽  
pp. 1251-1256
Author(s):  
J. Janu Sahana ◽  
S. Sriraghav ◽  
T. A. Vijeth ◽  
T. Nagarushyanth ◽  
R. Santhosh ◽  
...  
Keyword(s):  
Protein Structure ◽  
Efficient Method ◽  
Protein Structures ◽  
Three Dimensional ◽  
Structure And Function ◽  
The Other ◽  
Metal Coordination ◽  
And Function ◽  
Interacting Atoms ◽  
Best Fit

Metal ions play a considerable role in protein structure and function. The roles of most metals and their importance are determined by the arrangements of the interacting atoms in the three-dimensional protein structure. This information is essential in predicting the geometry of the atoms involved in metal coordination. The deviation of the other atoms from the best plane is another crucial factor. The proposed web server, PlaneFinder, provides a fast and efficient method to calculate the best-fit plane for a set of atoms involved in the metal coordination. It provides in addition other possible planes by considering the maximum number of interacting atoms as well as user-selected atoms. The deviations of the selected atoms and other atoms from the best-fit plane are also displayed. PlaneFinder is freely available and can be accessed at http://bioserver1.physics.iisc.ac.in/plane/.

scholarly journals Relationship between protein structure and function: Valuable insight from computational studies

2004 ◽  
Vol 26 (4) ◽  
pp. 13-16
Author(s):  
Mike Sutcliffe
Keyword(s):  
Protein Structure ◽  
Protein Function ◽  
Molecular Model ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Valuable Insight ◽  
Public And Private ◽  
Functional Roles ◽  
And Function

Life as we know it is sustained by the plethora of functional roles performed by proteins -- the precise function depending exquisitely on three-dimensional structure. The quest to understand protein function from structure has led worldwide to the establishment of a number of structural genomics projects and the concomitant substantial investment from both the public and private sectors, estimated to total around US$1 billion worldwide. Once a structure is solved, deducing function on the basis of this structure alone is often a non-trivial, but nonetheless essential, exercise -- mankind's pursuit of a complete, working molecular model of a cell is underway. This article discusses some of the computational approaches that assist in: (i) deducing function from protein structure, and (ii) elucidating factors at the atomic level that determine function. Far from replacing experimental studies, these approaches should be used to complement them -- the real value comes from an interdependent multidisciplinary approach.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Structure and function of neural networks in the retina

1988 ◽  
Vol 46 ◽  
pp. 26-27
Author(s):  
Peter Sterling
Keyword(s):  
Ganglion Cells ◽  
Three Dimensional ◽  
Structure And Function ◽  
Synaptic Connections ◽  
Visual Axis ◽  
One Dimensional ◽  
Cat Retina ◽  
Ultrathin Sections ◽  
And Function ◽  
Insight Into

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.

Structural Role of rRNAs on the Ribosomal Subunits from E. Coli by Scanning Transmission Electron Microscopy

1981 ◽  
Vol 39 ◽  
pp. 424-425
Author(s):  
M. Boublik ◽  
N. Robakis ◽  
J.S. Wall
Keyword(s):  
Three Dimensional ◽  
Uranyl Acetate ◽  
Dimensional Structure ◽  
Electron Microscopic ◽  
Ribosomal Subunits ◽  
E Coli ◽  
Freeze Dried ◽  
16S Rna ◽  
Scanning Transmission ◽  
And Function

The three-dimensional structure and function of biological supramolecular complexes are, in general, determined and stabilized by conformation and interactions of their macromolecular components. In the case of ribosomes, it has been suggested that one of the functions of ribosomal RNAs is to act as a scaffold maintaining the shape of the ribosomal subunits. In order to investigate this question, we have conducted a comparative TEM and STEM study of the structure of the small 30S subunit of E. coli and its 16S RNA.The conventional electron microscopic imaging of nucleic acids is performed by spreading them in the presence of protein or detergent; the particles are contrasted by electron dense solution (uranyl acetate) or by shadowing with metal (tungsten). By using the STEM on freeze-dried specimens we have avoided the shearing forces of the spreading, and minimized both the collapse of rRNA due to air drying and the loss of resolution due to staining or shadowing. Figure 1, is a conventional (TEM) electron micrograph of 30S E. coli subunits contrasted with uranyl acetate.

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