ABSTRACT
Thermostability improvement of enzymes used industrially or commercially would develop their capacity andcommercial potential due to increased enzymatic competence and cost-effectiveness. Several stabilizing factorshave been suggested to be the base of thermal stability, like proline replacements, disulfide bonds, surface looptruncation and ionic pair networks creation. This research evaluated the mechanism of increasing the rigidity oforganophosphorus hydrolase enzyme by flexible loop truncation. Bioinformatics analysis revealed that themutated protein retains its stability after loop truncation (five amino acids deleted). The thermostability of thewild-type (OPH-wt) and mutated (OPH-D5) enzymes were investigated by half-life, DGi, and fluorescence andfar-UV CD analysis. Results demonstrated an increase half-life and DGi in OPH-D5 compared to OPH-wt.These results were confirmed by extrinsic fluorescence and circular dichroism (CD) spectrometry experiments,therefore, as rigidity increased in OPHD5 after loop truncation, half-life and DGi also increased. Based onthese findings, a strong case is presented for thermostability improvement of OPH enzyme by flexible looptruncation after bioinformatics analysis.
ABSTRACT
AIM: To evaluate association between mutations in the visual system homeobox 1 (VSX1) gene and keratoconus (KCN) complicated with granular corneal dystrophy (GCD), direct sequencing was performed in an Iranian family affected by KCN and GCD in four generations.METHODS: An Iranian pedigree with keratoconus spanning four generations along with GCD was identified.Whole blood sample was used for genomic DNA extraction.The molecular analysis by using polymerase chain reaction (PCR) of the entire coding region and intron-exon boundaries of VSX1 gene was preformed to investigate the possible linkage between KCN and GCD.Subsequently, direct sequencing was used for PCR products and mutation analysis was conducted in the patients and controls.RESULTS: Mutation analysis in VSX1 gene did not detect evidence for association between KCN and GCD diseases and VSX1 gene.Our data excluded VSX1 as the disease-causing gene for KCN/GCD in this specific pedigree.CONCLUSION: Despite of no association between KCN patients with GCD and VSX1 gene variations, other probable genes involved in pathogenesis of the KCN and GCD diseases need to be investigated in the patients.
ABSTRACT
AIM: To evaluate intraocular lens power (IOL) calculation and biometry before and 3mo after implantation of Keraring 355° intrastromal corneal ring segment (ICRS;Mediphacos, Belo Horizonte, Brazil) in keratoconic eyes.METHODS: In this cohort study, data of 19 keratoconus eyes of 18 patients which undergone ICRS implantations were gathered before and 3mo after surgery.Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction, IOL power calculation formulas, axial lenght (AL) and keratometry were analayzed.RESULTS: Mean age of participants was 29.58±0.6.UCVA improved from 0.84 (0.35) logMAR to 0.43 (0.31) logMAR significantly (P<0.001).BCVA and AL didn`t change significantly after 3mo.All Sphere, cylinder and spherical equivalent (SE) were improved significantly (P<0.001).On the other hand, keratometry 1 (K1) and keratometry 2 (K2) decreased significantly.It was a considerable change in SRK/Ⅱ (P<0.001), Hoffer Q (P<0.001) and Holladay Ⅰ(P<0.001) after 3-month`s follow-up.Among this formula SRK/II had the lowest change.CONCLUSION: In addition to improvement in visual, refractive, and keratometry outcomes after Keraring implantation, there was a significantly changes in IOL calculation formulas values.However, ICRS procedure doesn`t interfere considerably AL in eyes, but it seems reduced keratometric values lead to IOL power calculations more accurately and all formulas suggested same IOL power.