The anti-oxidant enzyme, Prdx6 might have cis-acting regulatory sequence(s)

Structural and Functional Diversity of the Peroxiredoxin 6 Enzyme Family

Significance: Peroxiredoxins (Prdxs) with a single peroxidative cysteine (CP) in a conserved motif PXXX(T/S)XXCP within its thioredoxin fold, have been classified as the peroxiredoxin 6 (Prdx6 ) family. All Prdxs can reduce H2O2 and short chain hydroperoxides while Prdx6 in addition, can reduce phospholipid hydroperoxides (PLOOH) due to its ability to interact with peroxidized phospholipid substrate. The single CP of Prdx6 uses various external electron donors including glutathione thioredoxin, and ascorbic acid for resolution of its peroxidized state and, therefore, its peroxidase activity. Prdx6 proteins also exhibit Ca2+-independent phospholipase A2 (PLA2), lysophosphatidylcholine acyltransferase (LPCAT), and chaperone activities that depend on cellular localization and the oxidation and oligomerisation states of the protein. Thus, Prdx6 is a "moonlighting" enzyme. Recent Advance: Physiologically, Prdx6s have been reported to play an important role in protection against oxidative stress, repair of peroxidized cell membranes, mammalian lung surfactant turnover, activation of some NADPH oxidases, the regulation of seed germination in plants, as an indicator of cellular levels of reactive O2 species through Nrf-Klf9 activation, and possibly in male fertility, regulation of cell death through ferroptosis, cancer metastasis, and oxidative stress-related signalling pathways. Critical Issues: This review outlines Prdx6 enzyme unique structural features and explores its wide range of physiological functions. Yet, existing structural data falls short of fully revealing all of human Prdx6 multifunctional roles. Further endeavour is required to bridge this gap in its understanding. Although there are wide variations in both the structure and function of Prdx6 family members in various organisms, all Prdx6 proteins show the unique a long C-terminal extension that is also seen in Prdx1, but not in other Prdxs. Future Directions: As research data continues to accumulate, the potential for detailed insights into the role of C-terminal of Prdx6 in its oligomerisation and activities. There is a need for thorough exploration of structural characteristics of the various biological functions. Additionally, uncovering the interacting partners of Prdx6 and understanding its involvement in signalling pathways will significantly contribute to a more profound comprehension of its role.

Unveiling the Significance of Peroxiredoxin 6 in Central Nervous System Disorders

Peroxiredoxin 6 (Prdx6), a unique 1-Cys member of the peroxiredoxin family, exhibits peroxidase activity, phospholipase activity, and lysophosphatidylcholine acyltransferase (LPCAT) activity. Prdx6 has been known to be an important enzyme for the maintenance of lipid peroxidation repair, cellular metabolism, inflammatory signaling, and antioxidant damage. Growing research has demonstrated that the altered activity of this enzyme is linked with various pathological processes including central nervous system (CNS) disorders. This review discusses the distinctive structure, enzyme activity, and function of Prdx6 in different CNS disorders, as well as emphasizing the significance of Prdx6 in neurological disorders.

Insights into Fluctuations of Structure of Proteins: Significance of Intermediary States in Regulating Biological Functions

Proteins are indispensable to cellular communication and metabolism. The structure on which cells and tissues are developed is deciphered from proteins. To perform functions, proteins fold into a three-dimensional structural design, which is specific and fundamentally determined by their characteristic sequence of amino acids. Few of them have structural versatility, allowing them to adapt their shape to the task at hand. The intermediate states appear momentarily, while protein folds from denatured (D) ⇔ native (N), which plays significant roles in cellular functions. Prolific effort needs to be taken in characterizing these intermediate species if detected during the folding process. Protein folds into its native structure through definite pathways, which involve a limited number of transitory intermediates. Intermediates may be essential in protein folding pathways and assembly in some cases, as well as misfolding and aggregation folding pathways. These intermediate states help to understand the machinery of proper folding in proteins. In this review article, we highlight the various intermediate states observed and characterized so far under in vitro conditions. Moreover, the role and significance of intermediates in regulating the biological function of cells are discussed clearly.

De novo assembly and functional annotation of blood transcriptome of loggerhead turtle, and in silico characterization of peroxiredoxins and thioredoxins

The aim of this study was to generate and analyze the atlas of the loggerhead turtle blood transcriptome by RNA-seq, as well as identify and characterize thioredoxin (Tnxs) and peroxiredoxin (Prdxs) antioxidant enzymes of the greatest interest in the control of peroxide levels and other biological functions. The transcriptome of loggerhead turtle was sequenced using the Illumina Hiseq 2000 platform and de novo assembly was performed using the Trinity pipeline. The assembly comprised 515,597 contigs with an N50 of 2,631 bp. Contigs were analyzed with CD-Hit obtaining 374,545 unigenes, of which 165,676 had ORFs encoding putative proteins longer than 100 amino acids. A total of 52,147 (31.5%) of these transcripts had significant homology matches in at least one of the five databases used. From the enrichment of GO terms, 180 proteins with antioxidant activity were identified, among these 28 Prdxs and 50 putative Tnxs. The putative proteins of loggerhead turtles encoded by the genes Prdx1, Prdx3, Prdx5, Prdx6, Txn and Txnip were predicted and characterized in silico. When comparing Prdxs and Txns of loggerhead turtle with homologous human proteins, they showed 18 (9%), 52 (18%) 94 (43%), 36 (16%), 35 (33%) and 74 (19%) amino acid mutations respectively. However, they showed high conservation in active sites and structural motifs (98%), with few specific modifications. Of these, Prdx1, Prdx3, Prdx5, Prdx6, Txn and Txnip presented 0, 25, 18, three, six and two deleterious changes. This study provides a high quality blood transcriptome and functional annotation of loggerhead sea turtles.