Int J Pharm Pharm Sci, Vol 14, Issue 4, 28-33Original Article



1*Department Biotechnology, Vignan's Foundation for Science, Technology and Research, Guntur, Vadlamudi, Andhra Pradesh 522213
Email: [email protected]

Received: 24 Dec 2021, Revised and Accepted: 12 Feb 2022


Objective: RAD56 is a protein its causes pathological conditions of Kohler disease, Mueller-Weiss syndrome, which leads to hindfoot pain. RAD56 is considered an impressive drug target for various illnesses. The experimental 3D structure of RAD56 is not available. Therefore, the present study aims in developing a homology model using 3 different software and evaluate the best model.

Methods: The developing homology modeling on RAD56 is built utilizing three diverse software’s to be specific Swiss-Model, I-Tasser, and Phyre2. All the predicted models were analyzed and approved by PROCHECK, PROSA, Errat, and Verify_3D.

Results: Homology Modeling anticipated from Swiss-Model appeared best comes about with 88.6% of the buildups within the most favorable locale, 11.2% within the permitted region, 0.6% within the liberally permitted locale, and 0.2% within the refused locale. PROCHECK, PROSA, Errat, and Verify_3D, too, affirmed the same.

Conclusion: Homology Modeling was created for RAD56 utilizing Swiss-Model, I-Tasser, and Phyre2. The models created were validated utilizing PROCHECK, PROSA, Errat, and Verify_3D. This investigation approved the homology model created by is best Swiss-Model 88.6, vigorous as well as solid sufficient to be utilized for future pondering.

Keywords: RAD56, Homology modeling, Swiss-model, I-Tasser, Phyre2


RAD56 Protein causes pathological conditions of Kohler disease, Mueller-Weiss syndrome, which leads to hindfoot pain, and also proposing the N-terminal acetylation of particular DNA repair proteins is vital for effective DNA [1]. The test 3D structure of RAD56 isn't accessible. In this study, creating homology Model utilizing 3 diverse software and assessing the leading show. In this manner, the display work is an approach to plan used era candidate drugs to restrain RAD56 through in silico strategies.

Here we report the homology Modelling studies of the rad56 protein to the NAT3 gene, which encodes the catalytic subunit of the NatB N-terminal acetyltransferase in Saccharomyces cerevisiae. In this study, we think about the outline and clone RAD56 and we are grouping the first X-ray touchy rad56-1 mutant allele [2, 3]. The rad56-1 mutant encompasses a 1 base match erasure of A at position 639 within the NAT3 quality driving to a truncated Nat3 protein [4].

The exploratory 3D structure of RAD56 isn't accessible in this study there is required for the creation of the homology structure. The Computational approaches can be given to homology modeling, which can be encouraged used in atomic energetic recreations, and programmed docking to illustrate the work of proteins and to demonstrate the mode of substrate official [5, 6]. These sorts of strategies can be utilized successfully in enzyme-substrate frameworks and can provide valuable information for future considers. The most objective of this work is to present a three-dimensional (3D) model of RAD56 using 3 diverse software’s to be specific Swiss-Model (Schrodinger Inc), Phyre2 and I-Tasser, comparing the comes about and utilizing the leading demonstrate created for future study.

Homology modeling is one of the key discoveries that led to a rapid paradigm shift in the field of computational biology [7]. Homology modeling obtains the three-dimensional structure of a target protein based on the similarity between template and target sequences and this technique proves to be efficient when it comes to studying membrane proteins that are hard to crystallize like GPCR as it provides a higher degree of understanding of receptor-ligated interaction. There are several other common applications of homology models: (1) studying the effect of mutations (2) identifying active and binding sites on the protein.


Homology modeling

Homology modeling alludes to building an atomic-resolution model of the RAD56 protein from its corrosive amino arrangement and exploratory three-dimensional structure of homology modeling. The RAD56 protein is adjusted with the format the auxiliary structure is predicted between the two and the Model is created. The essential sequence of the target RAD56 was gotten from NCBI section title RAD56 [8, 9] [Saccharomyces cerevisiae], sequence length 195aa.

Table 1: Best hit obtained by PSI-BLAST with the RAD56 sequence

Accession Max score Total score Query cover E value Identity
NP_587922.1 169 169 100% 1e-52 45.41%
XP_643184.2 154 154 98% 1e-46 44.35%
NP_001014351.1 153 153 98% 3e-46 43.37%
NP_001014351.1 152 152 98% 8e-46 42.87%
NP_505053.1 151 151 89% 2e-45 42.10%

Fig. 1: Multiple sequence alignments of the target sequence with the template sequence

The exactness of the homology model is related to the degree of sequence personality and similitude between Protein and target. The selection of a reasonable layout and an ideal arrangement is fundamental to the victory of homology modeling. BLASTp was performed to discover a format structure of a known protein from Protein Data Bank (PDB). Layout distinguishing proof was performed using PSI-BLAST [10] to look at the non-redundant PDB database [12]. ( The best 5 hits recovered by the BLASTp program are appeared in (table 1). Different grouping arrangements of the inquiry and layouts were appeared in (fig. 1).

It identify the best 40% and 42% grouping identity; therefore, both the structures were utilized as formats to produce the model in Swiss-Model. The model was created utilizing Swiss-Model and the right arrangement between target and Protein can be decided by sequence-based strategies; visual review manual control of the arrangement can offer assistance progressing the quality of approach about Model. The other two software’s utilized to produce the homology show are I-TASSER and Phyre2. I-TASSER executes different threading calculations and iterative structure gathering reenactments to discover ideal sub-fragments inside database structures or inside a user-specified structure.

Phyre2 is unused GUI for Homology modeling may be a strategy that produces an already obscure protein structure by “fitting” its arrangement (target) into a known structure (layout), given a certain level of grouping homology. Inbuilt profile Watcher, Ramachandran plot, JSP model, and basic model optimization make its user-friendly software.

Evaluation of homology model

The approval of structure demonstrates gotten from Swiss-Model, I-Tasser, and Phyre2 were performed by reviewing the spine conformation of the modeled structure was calculated by analyzing the phi (φ) and psi (ψ) torsion points utilizing PROCHECK, as determined by Ramachandran plot. Based on an analysis of 118 structures of resolution of at least 2.0 Angstroms and R-factor no greater than 20%, a good quality model would be expected to have over 90% in the most favored regions. Residues in most favored regions [A, B, L] 156 88.6% Residues in additional allowed regions [a, b, l, p] 20 11.4% Residues in generously allowed regions [~a, ~b, ~l, ~p] 0 0.0% Residues in disallowed regions 0 0.0%. ERRAT could be a protein structure confirmation algorithm that is particularly well-suited for assessing the advancement of crystallographic show building and refinement. The program works by analyzing the measurements of non-bonded intelligence between different molecule sorts. Typically, greatly valuable in making choices about unwavering quality. Provecheck will give you a visual examination of the quality of a putative gem structure for a protein and analyzes the compatibility of a nuclear model of the protein with its amino acid arrangement.


Homology modelling using swiss-model

The Model was creating a given arrangement is the target sequence and which one compares to a known protein chain from the ExPDB layout library. The server will construct the show based on the given arrangement.

One advantage of Swiss-Model over other software’s modeling, to begin with, is to check the proper natural assembly of your template protein. Expel all non-amino corrosive residues. Ensure special chain IDs. Target sequence [13, 14]. Adjust target–template arrangement in Deep View.

All homology-modeling strategies comprise of the taking after four steps: (i) format choice,(ii) target layout arrangement, (iii) demonstrate building and (iv) assessment. These steps can be iteratively rehashed until a fulfilling demonstrate structure is accomplished. A few distinctive strategies for demonstrating building have been created. The Swiss-Model server approach can be portrayed as flexible part gathering [to begin with actualized in Composer, which can be sketched out briefly [15, 16].

The layout selection of the SWISS-MODEL server format library ExPDB is extricated from the PDB (1). In arrange to permit a steady and robotized workflow of the server, the PDB arrange records are part into person protein chains and untrustworthy passages, e. g., hypothetical models and moo quality structures giving as it were Cα arranges, are evacuated. Extra data valuable for layout choice is assembled and included in the record header; the final model was energy minimized with a truncated-Newton energy minimization using OPLS_2000 all-atom force field [25] (fig. 2A.). Every step was checked for improvement in the SAVES server and the final model after refinement had the best scores which were used for further validation (table 2).

1. Phyre2 2. Swiss-model 3. I-Tasser

Fig. 1: Homology modelling of RAD56 protein using swiss-model, Phyre2, I-Tasser

Table 2: Comparative values of procheck, errat, verify_3D, prove in different stages of refinement used in swiss-model software

Validation After modeling Refine loop Minimize Predict side chain
Ramachandran plot allowed 88.6% 89.1% 83.3% 88.2%
Disallowed 0.2% 0.1% 0.0% 0.0%
Errat 83.3% 83.8% 84.5% 84.4%
Verify_3D 68.33% 70.1% 68.1% 68.1%
Prove_z-score 0.68 0.58 0.57 0.52

Homology modeling using I-TASSER

In this strategy, the target groupings are, to begin with, strung employing a representative PDB structure library to explore for the conceivable folds by profile-profile Arrangement (PPA), Covered up Markov Show, PSI-BLAST profiles, Needleman-Wunch, and Smith-Waterman arrangement algorithms. The PDB had the best Z-score utilizing all the ten calculations and was utilized for modeling the RAD56 structure (table 3). I-TASSER server anticipated 5 models from which the demonstrate with best C-Score of 1.62 was selected with estimated exactness of 0.91(TM-Score) and 4.3Å (RMSD) (fig. 2B). The score may be a certainty score for assessing the quality of predicted models by I-TASSER. It is calculated based on the noteworthiness of threading layout arrangements and the meeting parameters of the structure get-together simulations.

Homology modeling using PHYRE2

Phyre and Phyre2 (Protein Homology/Analogy Acknowledgment Motor) are free web-based administrations for protein structure forecast. Phyre is among the foremost well-known strategies for protein structure forecast, having been cited over 1500 times. After gluing a protein amino corrosive grouping into the Phyre or Phyre2 accommodation frame, a client will ordinarily hold up between 30 min and a few hours (depending on variables such as arrangement length, number of homologous arrangements and recurrence and length of inclusions and cancellations) for a forecast to the total. A mail containing outline data and the anticipated structure in PDB arrange are sent to the client in conjunction with an interface to a web page of comes about. The Phyre2 comes about the screen is partitioned into three primary segments, one is Auxiliary structure and clutter prediction, Domain investigation and Nitty-gritty format data.

Were analyzed utilizing different structure evaluation [16, 17] Show from prime demonstrated that 88.6% of the build-ups within the most favorable locale, 156 within the allowed locale, 11.4% within the liberally permitted locale, and 0.0% in the refused locale Program.

Model validation

1. Swiss-model 2. Phyre2 3. I-Tasser

Fig. 3: Ramachandran Plot for the modeled RAD56 after refinement. The red, yellow, and white regions represent the favored, allowed, and disallowed regions, respectively

  1. Swiss-model

2. Phyre2

3. I-Tasser

Fig. 4: ERRAT plot of ADAM12 modeled by (a) Swiss-model, (b) Phyre2, (C) I-Tasser, and overall quality factor or ERRAT score

These come about uncovered that the larger part of the amino acids is in phi-psi dissemination that's reliable with a program. Ramachandran plot calculations were calculated with PROCHECK Approval of the demonstrate counting the geometric properties of the backbone conformations, Ramachandran plot of the three models was appeared in (fig. 3A). The plot is Present in the Alpha helix and beta sheets. Right-handed α-helix and the demonstrate is dependable and of great quality. Though the other two models did not have such best scores compared with prime (fig. 3B and 3C). The show created by the Swiss model had a Z score of 4.89, showing that the demonstration created by Swiss-model it was very great though the other two models come within the criteria of the decently good model with an LG score of 2. ERRAT (fig. 4), Verify_3D, Prove, Pros A (fig. 5 and 6).

1. Swiss-model 2. Phyre2 3. I-Tasser

Fig. 5: Pros A-web Z-scores of RAD56 model (black Spot) concerning all protein chains in PDB determined by X-ray crystallography (light blue) or NMR spectroscopy (dark blue) to their length

1. Swiss-model 2. Phyre2 3. I-Tasser

Fig. 6: Residue energy plots of RAD56 from swiss-model, Phyre2, and I-tasser

Table 3: Comparative values of Procheck, ProQ, Errat, Verify_3D, Prove, ProSA Z-scores between the Template and Modelled protein of all the three models

Validation Swiss-model I-Tasser Phyre 2
Ramachandran Plot- Allowed region 88.6% 72.1% 89.7%
Additionally allowed 11.4% 4.5 % 7.5%
Generously allowed 0.0% 8.5% 2.3%
Disallowed region 0.0% 4.2% 0.6%
ProSA Z-score -5.6% -3.5 -4.0
Errat 88.2% 70.2% 89.2%
Verify_3D 70.1% 62.3% 68.4%

1. Swiss-model 2. Phyre2 3. I-Tasser

Fig. 7: JS Model of RAD56 (a). Swiss-Model,(b). Phyre2, (c) I-Tsser

Fig. 8: Normalize B-factor analysis of RAD56

Fig. 9: Estimate accuracy of residues of RAD56


RAD56 is a protein its causes pathological conditions of Kohler disease, Mueller-Weiss syndrome, which leads to hindfoot pain. The test 3D structure of RAD56 is not accessible. In this study, creating a model. In this study, RAD56 is considered as a critical medicate target for different maladies. Within the present work, a homology-based 3D show of RAD56 is constructed utilizing three diverse software’s to be specific SWISS-MODEL, I-Tasser, and PHYRE2 program.

The most excellent models delivered by all software were assisted surveyed by Procheck, Errat, Verify_3D, ProSA. Based on the results, it can be recommended that the Swiss-Model Demonstrate computer program delivered satisfactory Ramachandran plot insights, Errat plot quality figures. Moreover, the online approval server (ProSA web) appeared that the Z-score and vitality of protein collapsing of the models was in great assertion with the accessible protein structures in PDB, which favored the general quality of the structures. These investigations validated the homology demonstrated delivered by Swiss-Model is strong as well as dependable sufficient to be utilized for Medicate Revelation.


I sincerely thank Vignan University for its constant support.




All the work has been carried out by me.


The author declares no conflicts of interest.


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