ABSTRACT
The goals were to analyze and characterize the secondary structure, regions of intrinsic disorder and physicochemical characteristics of three classes of mutations described in the enzyme N-acetylgalactosamine-6-sulfatase that cause mucopolysaccharidosis IVA: missense mutations, insertions and deletions. All mutations were compared to wild-type enzyme, and the results showed that with 25 of 129 missense mutations secondary structure was maintained and that 104 mutations showed minor changes, such as an increase or decrease in the size of the elements. The secondary structure of all insertions and deletions introduced important changes, such as increase in the number and size of elements. The results obtained from intrinsic disorder analysis revealed that missense mutations caused no alterations. However, the insertions and deletions led to major regions of intrinsic disorder. The physicochemical characteristics of the amino acids found in missense mutations revealed unchanged characteristics in 32 of the 129 mutations. However, the remainder had changes that could lead to a modification of tertiary structure. The results proved that it was feasible and necessary to obtain the three-dimensional structure of the enzyme with its mutants to better understand the change in function.
Subject(s)
Chondroitinsulfatases/genetics , Computer Simulation , Genetic Predisposition to Disease , Mucopolysaccharidoses/enzymology , Mucopolysaccharidoses/genetics , Mutation/genetics , Chondroitinsulfatases/chemistry , Humans , Intrinsically Disordered Proteins/chemistry , Intrinsically Disordered Proteins/genetics , Protein Structure, SecondaryABSTRACT
The shelf life of fresh Italian pork sausages packed in modified atmosphere was studied. Samples were packed using different levels of oxygen (high and low) with different levels of carbon dioxide (high-low) in the atmospheres headspace and were stored at 4 °C for 9 days. Microbial, physiochemical and sensory parameters were analyzed during storage. A consumer test was performed to determine the critical acceptability levels. Sensory data were mathematically modelled to estimate product shelf life. A first-order kinetic model and a Weibull-type model aptly described, respectively, the changes in fresh pork sausage odor and color over storage time. These models may be used to predict the sensory shelf life of fresh pork sausage. Results showed that 20% O(2) and 70% CO(2) extend fresh pork sausage shelf life to 9 days at 4 °C. The microbial quality of the samples at the critical sensory level of acceptability was within the range of microbial acceptability.
