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941.
Fluorescence resonance energy transfer (FRET) provides a powerful means to study protein conformational changes. However, the incorporation of an exogenous FRET pair into a protein could lead to undesirable structural perturbations of the native fold. One of the viable strategies to minimizing such perturbations is to use non-natural amino acid-based FRET pairs. Previously, we showed that p-cyanophenylalanine (PheCN) and tryptophan (Trp) constitute such a FRET pair, useful for monitoring protein folding-unfolding transitions. Here we further show that 7-azatryptophan (7AW) and 5-hydroxytryptophan (5HW) can also serve as a FRET acceptor to PheCN, and the resultant FRET pairs offer certain advantages over PheCN-Trp. For example, the fluorescence spectrum of 7AW is sufficiently separated from that of PheCN, making it straightforward to decompose the FRET spectrum into donor and acceptor contributions. Moreover, we show that PheCN, Trp, and 7AW can be used together to form a multi-FRET system, allowing more structural information to be extracted from a single FRET experiment. The applicability of these FRET systems is demonstrated in a series of studies where they are employed to monitor the urea-induced unfolding transitions of the villin headpiece subdomain (HP35), a designed ββα motif (BBA5), and the human Pin1 WW domain. 相似文献
942.
Tobias Bartek Enrico Zönnchen Bianca Klein Robert Gerstmeir Pia Makus Siegmund Lang Marco Oldiges 《Journal of industrial microbiology & biotechnology》2010,37(3):263-270
l-Valine biosynthesis was analysed by comparing different plasmids in pyruvate-dehydrogenase-deficient Corynebacterium glutamicum strains in order to achieve an optimal production strain. The plasmids contained different combinations of the genes ilvBNCDE encoding for the l-valine forming pathway. It was shown that overexpression of the ilvBN genes encoding acetolactate synthase is obligatory for efficient pyruvate conversion and to prevent l-alanine as a by-product. In contrast to earlier studies, overexpression of ilvE encoding transaminase B is favourable in pyruvate-dehydrogenase-negative strains. Its amplification enhanced l-valine formation and avoided extra- and intracellular accumulation of ketoisovalerate. 相似文献
943.
Rummel Pauline Sophie Well Reinhard Pfeiffer Birgit Dittert Klaus Floßmann Sebastian Pausch Johanna 《Plant and Soil》2021,459(1-2):217-233
Plant and Soil - Plant growth affects soil moisture, mineral N and organic C availability in soil, all of which influence denitrification. With increasing plant growth, root exudation may stimulate... 相似文献
944.
Ionică Loredana N. Gaiță Laura Bînă Anca M. Soșdean Raluca Lighezan Rodica Sima Alexandra Malița Daniel Crețu Octavian M. Burlacu Ovidiu Muntean Danina M. Sturza Adrian 《Molecular and cellular biochemistry》2021,476(11):4019-4029
Molecular and Cellular Biochemistry - In the past decade, monoamine oxidase (MAO) with 2 isoforms, MAO-A and B, has emerged as an important source of mitochondrial reactive oxygen species (ROS) in... 相似文献
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947.
E M Be?er 《Biokhimii?a (Moscow, Russia)》1977,42(5):881-889
The effect of a partially purified preparation of pig kidney alpha-L-fucosidase on some glycoproteins--human and rabbit gamma-globulin, glycoprotein from sheep submaxillary gland and ceruloplasmin--was studied. It was shown that the action of the enzyme of the glycoproteins was not accompanied by a release of fucose. A comparative study of the properties of free and concanavalin A-Sepharose 4B-bound alpha-L-fucosidase was done. The experimental data is indicative of difference in the pH-dependenced and thermostability of these two enzyme forms. It was found that bound alpha-L-fucosidase, similar to the free form, did not split off fucose from the native blood group substances. The data of isoelectric fucosing of alpha-L-fucosidase suggests the existence of enzyme polymorphism. 相似文献
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949.
Philip Lewis Martin Hellmich Lin Fritschi Gabriella Tikellis Peter Morfeld J. Valérie Groß 《Chronobiology international》2020,37(7):1034-1047
ABSTRACT Experimental evidence suggests that perinatal light imprinting of circadian clocks and systems may affect downstream physiology and cancer risk in later life. For humans, the predominant circadian stimulus is the daily light-dark cycle. Herein, we explore associations between perinatal photoperiod characteristics (photoperiod: duration of daylight as determined by time-of-year and location) and childhood cancer risk. We use pooled data on 182,856 mothers and babies from prospective birth cohorts in six countries (Australia, Denmark, Israel, Norway, UK, USA) within the International Childhood Cancer Cohort Consortium (I4C). Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). In line with predicted differential dose–responses, restricted cubic splines indicate a potential non-linear, non-monotonic relationship between perinatal mean daily photoperiod (0–24 h) and childhood cancer risk. In a restricted analysis of 154,121 individuals who experienced third trimester photoperiods exclusively within the 8–16-h range, the relative risk of developing childhood cancer decreased by 9% with every hour increase in third trimester mean daily photoperiod [HR: 0.91 (95%CIs: 0.84–0.99)]. In conclusion, in this first study of perinatal photoperiod and childhood cancer, we detected an inverse [“protective”] linear association between third trimester mean daily photoperiod and childhood cancer risk in the 8–16-h set of the total study population. Limited statistical power impeded the investigation of risks with individuals exposed to more extreme photoperiods. Future studies are needed to confirm differential photoperiod-associated risks and further investigations into the hypothesized circadian imprinting mechanism are warranted. 相似文献
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