Guzzi A F, Oliveira F S L, Amaro M M S, Tavares-Filho P F, Gabriel J E
Universidade Federal do Vale do São Francisco - UNIVASF, Campus Sede, Av. José de Sá Maniçoba, s/n, Centro, CEP 56304-917, Petrolina, PE, Brasil.
Braz J Biol. 2020 Jan-Feb;80(1):39-46. doi: 10.1590/1519-6984.188655.
The current study aimed to assess whether the A122V causal polymorphism promotes alterations in the functional and structural proprieties of the CXC chemokine receptor type 1 protein (CXCR1) of cattle Bos taurus by in silico analyses. Two amino acid sequences of bovine CXCR1 was selected from database UniProtKB/Swiss-Prot: a) non-polymorphic sequence (A7KWG0) with alanine (A) at position 122, and b) polymorphic sequence harboring the A122V polymorphism, substituting alanine by valine (V) at same position. CXCR1 sequences were submitted as input to different Bioinformatics' tools to examine the effects of this polymorphism on functional and structural stabilities, to predict eventual alterations in the 3-D structural modeling, and to estimate the quality and accuracy of the predictive models. The A122V polymorphism exerted tolerable and non-deleterious effects on the polymorphic CXCR1, and the predictive structural model for polymorphic CXCR1 revealed an alpha helix spatial structure typical of a receptor transmembrane polypeptide. Although higher variations in the distances between pairs of amino acid residues at target-positions are detected in the polymorphic CXCR1 protein, more than 97% of the amino acid residues in both models were located in favored and allowed conformational regions in Ramachandran plots. Evidences has supported that the A122V polymorphism in the CXCR1 protein is associated with increased clinical mastitis incidence in dairy cows. Thus, the findings described herein prove that the replacement of the alanine by valine amino acids provokes local conformational changes in the A122V-harboring CXCR1 protein, which could directly affect its post-translational folding mechanisms and biological functionality.
本研究旨在通过计算机分析评估A122V因果多态性是否会促进牛Bos taurus CXC趋化因子受体1型蛋白(CXCR1)的功能和结构特性发生改变。从数据库UniProtKB/Swiss-Prot中选取了两个牛CXCR1的氨基酸序列:a)在第122位为丙氨酸(A)的非多态性序列(A7KWG0),以及b)携带A122V多态性的多态性序列,该序列在相同位置将丙氨酸替换为缬氨酸(V)。将CXCR1序列作为输入提交给不同的生物信息学工具,以检查这种多态性对功能和结构稳定性的影响,预测三维结构模型中的最终变化,并估计预测模型的质量和准确性。A122V多态性对多态性CXCR1产生了可耐受且无害的影响,多态性CXCR1的预测结构模型显示出受体跨膜多肽典型的α螺旋空间结构。尽管在多态性CXCR1蛋白中检测到目标位置的氨基酸残基对之间的距离变化更大,但两个模型中超过97%的氨基酸残基位于拉氏图中的有利和允许构象区域。有证据支持CXCR1蛋白中的A122V多态性与奶牛临床乳腺炎发病率增加有关。因此,本文所述的研究结果证明,丙氨酸被缬氨酸取代会在携带A122V的CXCR1蛋白中引起局部构象变化,这可能直接影响其翻译后折叠机制和生物学功能。