Stabilization of secondary structure elements by specific combinations of hydrophilic and hydrophobic amino acid residues is more important for proteins encoded by GC-poor genes

Biochimie ◽  
2012 ◽  
Vol 94 (12) ◽  
pp. 2706-2715 ◽  
Author(s):  
Vladislav Victorovich Khrustalev ◽  
Eugene Victorovich Barkovsky
Author(s):  
Wei He ◽  
Wenhui Zhang ◽  
Zhenhua Chu ◽  
Yu Li

The aim of this paper is to explore the mechanism of the change in oestrogenic activity of PCBs molecules before and after modification by designing new PCBs derivatives in combination with molecular docking techniques through the constructed model of oestrogenic activity of PCBs molecules. We found that the weakened hydrophobic interaction between the hydrophobic amino acid residues and hydrophobic substituents at the binding site of PCB derivatives and human oestrogen receptor alpha (hERα) was the main reason for the weakened binding force and reduced anti-oestrogenic activity. It was consistent with the information that the hydrophobic field displayed by the 3D contour maps in the constructed oestrogen activity CoMSIA model was one of the main influencing force fields. The hydrophobic interaction between PCB derivatives and oestrogen-active receptors was negatively correlated with the average distance between hydrophobic substituents and hydrophobic amino acid residues at the hERα-binding site, and positively correlated with the number of hydrophobic amino acid residues. In other words, the smaller the average distance between the hydrophobic amino acid residues at the binding sites between the two and the more the number of them, and the stronger the oestrogen activity expression degree of PCBS derivative molecules. Therefore, hydrophobic interactions between PCB derivatives and the oestrogen receptor can be reduced by altering the microenvironmental conditions in humans. This reduces the ability of PCB derivatives to bind to the oestrogen receptor and can effectively modulate the risk of residual PCB derivatives to produce oestrogenic activity in humans.


2016 ◽  
Vol 45 (23) ◽  
pp. 9436-9445 ◽  
Author(s):  
Takaaki Miyamoto ◽  
Yuta Fukino ◽  
Shinichiro Kamino ◽  
Masashi Ueda ◽  
Shuichi Enomoto

The stability of Cu2+–ATCUN complexes under physiologically relevant conditions is enhanced by inserting bulky and hydrophobic residues at positions 1 and 2 of the ATCUN peptide.


1983 ◽  
Vol 3 (3) ◽  
pp. 225-232 ◽  
Author(s):  
Hans Jórnvall ◽  
Bengt Persson

Distributions of amino acid residues in proteins show that proline is overrepresented in sequence positions following two basic residues ({LysArg}−{LysArg}), i.e. at sites similar to those susceptible to proteolytic cleavages of hormonal pro-forms. Conformational correlations further show that {LysArg}−{LysArg}-Pro sequences are often (8/11) not adiacent to elements of secondary structure, whereas the opposite applies to {LysArg}−{LysArg}-nonPro sequences (82/103 adjacent to elements of secondary structure). These distribution patterns from proteins in general also seem applicable in individual protein groups as demonstrated for some dehydrogenases. It appears possible that {LysArg}−{LysArg}-nonPro constitutes a restricted sequence, n proteins, and that proline, in addition to elements of secondary structure, contributes a means of avoiding unacceptable proteolytic processings of proteins in general.


2020 ◽  
Vol 17 (2) ◽  
pp. 95-106
Author(s):  
Neerja Thakur ◽  
Nikhil Sharma ◽  
Vijay Kumar ◽  
Tek Chand Bhalla

Background: Amidases are ubiquitous enzymes and biological functions of these enzymes vary widely. They are considered to be synergistically involved in the synthesis of a wide variety of carboxylic acids, hydroxamic acids and hydrazides, which find applications in commodity chemicals synthesis, pharmaceuticals agrochemicals and wastewater treatments. Methods: They hydrolyse a wide variety of amides (short-chain aliphatic amides, mid-chain amides, arylamides, α-aminoamides and α-hydroxyamides) and can be grouped on the basis of their catalytic site and preferred substrate. Despite their economic importance, we lack knowledge as to how these amidases withstand elevated pH and temperature whereas others cannot. Results: The present study focuses on the statistical comparison between the acid-tolerant, alkali tolerant and neutrophilic organisms. In silico analysis of amidases of acid-tolerant, alkali tolerant and neutrophilic organisms revealed some striking trends as to how amino acid composition varies significantly. Statistical analysis of primary and secondary structure revealed amino acid trends in amidases of these three groups of bacteria. The abundance of isoleucine (Ile, I) in acid-tolerant and leucine (Leu, L) in alkali tolerant showed the aliphatic amino acid dominance in extreme conditions of pH in acidtolerant and alkali tolerant amidases. Conclusion: The present investigation insights physiochemical properties and dominance of some crucial amino acid residues in the primary and secondary structure of some amidases from acid-tolerant, alkali tolerant and neutrophilic microorganisms.


2004 ◽  
Vol 279 (50) ◽  
pp. 52781-52788 ◽  
Author(s):  
Akira Morimoto ◽  
Kazuhiro Irie ◽  
Kazuma Murakami ◽  
Yuichi Masuda ◽  
Hajime Ohigashi ◽  
...  

Amyloid fibrils in Alzheimer's disease mainly consist of 40- and 42-mer β-amyloid peptides (Aβ40 and Aβ42) that exhibit aggregative ability and neurotoxicity. Although the aggregates of Aβ peptides are rich in intermolecular β-sheet, the precise secondary structure of Aβ in the aggregates remains unclear. To identify the amino acid residues involved in the β-sheet formation, 34 proline-substituted mutants of Aβ42 were synthesized and their aggregative ability and neurotoxicity on PC12 cells were examined. Prolines are rarely present in β-sheet, whereas they are easily accommodated in β-turn as a Pro-Xcorner. Among the mutants at positions 15-32, only E22P-Aβ42 extensively aggregated with stronger neurotoxicity than wild-type Aβ42, suggesting that the residues at positions 15-21 and 24-32 are involved in the β-sheet and that the turn at positions 22 and 23 plays a crucial role in the aggregation and neurotoxicity of Aβ42. The C-terminal proline mutants (A42P-, I41P-, and V40P-Aβ42) hardly aggregated with extremely weak cytotoxicity, whereas the C-terminal threonine mutants (A42T- and I41T-Aβ42) aggregated potently with significant cytotoxicity. These results indicate that the hydrophobicity of the C-terminal two residues of Aβ42 is not related to its aggregative ability and neurotoxicity, rather the C-terminal three residues adopt the β-sheet. These results demonstrate well the large difference in aggregative ability and neurotoxicity between Aβ42 and Aβ40. In contrast, the proline mutants at the N-terminal 13 residues showed potent aggregative ability and neurotoxicity similar to those of wild-type Aβ42. The identification of the β-sheet region of Aβ42 is a basis for designing new aggregation inhibitors of Aβ peptides.


2020 ◽  
Vol 65 (6) ◽  
pp. 1065-1071
Author(s):  
А.Н. Некрасов ◽  
◽  
Ю.П. Козмин ◽  
С.В. Козырев ◽  
Н.Г. Есипова ◽  
...  

This research investigates 24 647 non-homologous protein sequences. The occurrence profile of peptapeptides was constructed for every sequence and hierarchically organized elements of various sizes were revealed by a special mathematical method in each profile. The correlations between these hierarchical elements were analyzed and it was shown that in a tested set of protein sequences there are 11 levels of protein organization with elements ranging in length from 7 to 56 amino acid residues. It was suggested that the identified levels of organization correspond to elements of a super-secondary structure with different topology.


1986 ◽  
Vol 52 (5) ◽  
pp. 859-862 ◽  
Author(s):  
Eiji Niwa ◽  
Shin-ichiro Kohda ◽  
Teruo Nakayama

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