A cDNA coding for a plastidic P2-type G6PDH isoform from poplar (Populus tremula x tremuloides) has been used to express and purify to homogeneity the mature recombinant protein with a N-terminus His-tag. The study of the kinetic properties of the recombinant enzyme showed an in vitro redox sensing modulation exerted by reduced DTT. The interaction with thioredoxins (TRXs) was then investigated. Five cysteine to serine variants (C145S - C175S - C183S - C195S - C242S) and a variant with a double substitution for Cys and Cys (C175S/C183S) have been generated, purified and biochemically characterized in order to investigate the specific role(s) of cysteines in terms of redox regulation and NADPH-dependent inhibition. Three cysteine residues (C, C, C) are suggested to have a role in controlling the NADP access to the active site, and in stabilizing the NADPH regulatory binding site. Our results also indicate that the regulatory disulfide involves residues Cys and Cys in a position similar to those of chloroplastic P1-G6PDHs, but the modulation is exerted primarily by TRX m-type, in contrast to P1-G6PDH, which is regulated by TRX f. This unexpected specificity indicates differences in the mechanism of regulation, and redox sensing of plastidic P2-G6PDH compared to chloroplastic P1-G6PDH in higher plants.
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http://dx.doi.org/10.1016/j.plantsci.2016.08.003 | DOI Listing |
Proteins have proven to be useful agents in a variety of fields, from serving as potent therapeutics to enabling complex catalysis for chemical manufacture. However, they remain difficult to design and are instead typically selected for using extensive screens or directed evolution. Recent developments in protein large language models have enabled fast generation of diverse protein sequences in unexplored regions of protein space predicted to fold into varied structures, bind relevant targets, and catalyze novel reactions.
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January 2025
Department of Biological Sciences, Chungnam National University, Daejeon, Korea.
Previous studies have identified three families of knotted phytochrome photoreceptors in cyanobacteria. We describe a fourth type: 'hybrid' phytochromes with putative bilin-binding cysteine residues in both their N-terminal 'knot' extensions and cGMP-phosphodiesterase/adenylate cyclase/FhlA (GAF) domains, which we designate as dual-cysteine bacteriophytochromes (DCBs). Recombinant expression of DCBs in Escherichia coli yields photoactive phycocyanobilin (PCB) adducts with red/far-red photocycles similar to those of the GAF-Cys-containing cyanobacterial phytochromes (Cph1s).
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January 2025
Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany; Institute of Clinical Human Genetics, University Hospital Regensburg, 93053 Regensburg, Germany. Electronic address:
BCL11B is a Cys2-His2 zinc-finger (C2H2-ZnF) domain-containing, DNA-binding, transcription factor with established roles in the development of various organs and tissues, primarily the immune and nervous systems. BCL11B germline variants have been associated with a variety of developmental syndromes. However, genotype-phenotype correlations along with pathophysiologic mechanisms of selected variants mostly remain elusive.
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December 2024
Department of Biology Education, Daegu University, 201, Daegudae-ro, Gyeongsan-si 38453, Gyeongsangbuk-do, Republic of Korea.
Cathepsin K plays a pivotal role in bone resorption and has emerged as a prominent therapeutic target for treating bone-related diseases such as osteoporosis. Despite significant advances in synthetic inhibitor development, none have achieved FDA approval due to safety and efficacy challenges. This review highlights the potential of phytochemicals as alternative inhibitors, emphasizing their natural origin, structural diversity, and minimal adverse effects.
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December 2024
Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
Scorpion venom contains various bioactive peptides, many of which exhibit insecticidal activity. The majority of these peptides have a cystine-stabilized α-helix/β-sheet (CSαβ) motif. In addition to these peptides, scorpion venom also contains those with a cystine-stabilized α-helix/α-helix (CSαα) motif, which are known as κ-KTx peptides.
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