Protein damage, detection

Detection of Protein Damage Arising the Radical-mediated Peroxidation of ... 

Not all data confirm accumulation of protein oxidation products with age. For example, comparison of 9-month-old and 24-month-old female Long-Evans/Wistar hybrid rats did not demonstrate any age-related increase of o-tyrosine and 3-nitrotyrosine in the heart, skeletal muscle, and liver. These observations were interpreted as indications suggesting that proteins damaged by the hydroxyl radical and reactive nitrogen species did not accumulate in these tissues with advancing age (L7). Dityrosine could not be detected in human plasma proteins or haemoglobin (with the detection limit of 1 pmol/mg protein) (D3), but may accumulate in... 

Second checkpoint - Another checkpoint occurs when the protein p53 detects DNA damage. When damage is detected, p53 activates transcription of the gene PicI, the product of which binds to CDCKs, blocking the cell in the G1 phase and frequently leading to apoptosis. If p53 is unable to function, potentially cancerous cells with damaged DNA will be able to replicate. 

Proof of ROS-mediated DI protein damage is a decrease in electrophoretic mobility of the original Dl protein band." " Most probably it is a consequence of conformational changes in protein secondary stmcture, mainly in the content of the a-helices and P-sheets, as was detected by FTIR spectroscopy in parallel with degradation of the Dl protein.Oxidation of proteins could be confirmed by detection of carbonyl groups that were used as a marker of ROS-mediated protein oxidation." ... 

PARP-1 is a signaling enzyme that transfers ADP-ribose groups from NAD to itself and other nuclear proteins in response to detecting DNA damage. Poly(ADP)ribosylation of histones has been shown to loosen chromatin (de Murcia et al, 1986), indicating that damage detection by PARP-1 leads to increased access to the site of damage for other repair... 

The responses of TV 1061 demonstrate its usefullness as a biosensor for the detection of protein damaging toxicity. This strain combined with the minibioreactors provided a system which was consistent and reliable. Theoretically,... 

For future research in this field, in addition to physiological and biochemical approaches, genetic analysis will be essential in the establishment of causal relationships between the induction of a stress protein and the establishment of tolerance to the stress condition. In most cases it is not difficult to detect the induction of new proteins during stress. However, the induction of new proteins does not necessarily establish stress tolerance it may well be the consequence of damage caused by stress conditions. Thus, genetic mutants will be necessary to test the physiological role of a stress protein. 

Alpha-l-antiprotease (ai-AP) limits tissue damage arising from the actions of the leucocyte protease, elastase (Carrell and Travis, 1985), and there is much evidence available for the oxidative inactivation of this protein by oxygen-derived free-radical species and hypochlorous acid/hypochlorite anion (HOCl/OCP). The mechanism of this inactivation appears to involve the oxidation of a critical methionine residue (Met-358) to its corresponding sulphoxide and methionine sulphoxide has been detected in ai-AP samples isolated from the lungs of cigarette smokers (Carp et al., 1982) and rheumatoid synovial fluids (Wong and Travis, 1980). 

A protease-specific model has also been reported in which a replication-defective adenovirus encoding an NS3 protease-SEAP fusion protein is injected into mouse tail veins, resulting in expression of the fusion protein in the liver [82, 83]. Protease activity can be detected both by measuring activity of liberated SEAP or by protease-induced liver damage. Protease activity was found to be reduced by administration of protease inhibitors. This model can be used to show that candidate inhibitors have adequate pharmacokinetic properties in mice to function in the intended target organ, but it is not a true disease model. 

DNA CT also permits chemistry at a distance. Oxidative DNA damage and thymine dimer repair can proceed in a DNA-mediated reaction initiated from a remote site. These reactions too are sensitive to intervening DNA dynamical structure, and such structures can serve to modulate DNA CT chemistry. The sensitivity of DNA CT to base pair stacking also provides the basis for the design of new DNA diagnostics, tools to detect mutations in DNA and to probe protein-DNA interactions. 

---