Structural and functional consequences of replacement of His403 with Arg near the catalytic site of Anoxybacillus flavithermus cyclomaltodextrinase.

The hydrolytic activity of a thermophilic cyclomaltodextrinase (CMD) from Anoxybacillus flavithermus ZNU-NGA and a representative single mutant were investigated against soluble substrates including α-, β- and γ-cyclomaltodestrines (CDs). Based on the occurrence of arginine (Arg) at position 403 in some homologue proteins, His in Wild-type (WT) CMD was replaced with Arg (H403R variant) with site-directed mutagenesis procedures. According to bioinformatics data, Arg in mutant protein is located near Glu as one of the catalytic residues in a manner that they are able to create a medium-range attractive electrostatistic interaction.

Thermodynamics of protein folding: methodology, data analysis and interpretation of data.

Thermodynamics of protein folding refers to the stability measurements where structural changes of a given protein in the presence of a denaturing agent are monitored by spectroscopic or calorimetric techniques. In macroscopic point of view, protein stability represents the ratio of the population of its unfolded state to that of folded one in equilibrium condition, while in microscopic point of view, the stability is actually a net value from a combination of favorable and unfavorable contributions that affect the structural integrity of a protein molecule. In this manuscript, the principles and methodological aspects of thermodynamic studies and methods of data analysis as well as interpretation of the results are presented.

Molecular mechanisms governing the evolutionary conservation of Glycine in the 6 position of loops ΙΙΙ and ΙV in photoprotein mnemiopsin 2.

Photoproteins in their functional form are complexed noncovalently with 2-hydroperoxycoelenterazine. A conformational change upon coordination of Ca ions with their EF-hand loops leads to oxidation of substrate and emission of light. In all photoproteins, EF-hand loops Ι, ΙΙΙ and ΙV have standard sequence for binding to Ca ion, however the second one is not able for Ca coordination.

Investigating the structural and functional features of representative recombinants of chondroitinase ABC I.

Chondroitin Sulfate Proteoglycans (CSPGs) are the main inhibitors for axon regeneration after damaging of Central Nervous System (CNS). Chondroitinase ABC I (cABC I) can degrade CSPGs by removing chondroitin and dermatan sulfate side chains from proteoglycans. Hence, it may be considered as an attractive candidate in biomedicine.