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81.
82.
Stefano Raimondi Daniela Uccelletti Alberto Amaretti Alan Leonardi Claudio Palleschi Maddalena Rossi 《Applied microbiology and biotechnology》2010,86(3):871-878
The Kluyveromyces lactis Cu/Zn SOD gene (SOD1) was fused with the toxin K1 signal sequence to obtain extracellular production of superoxide dismutase. Kluyveromyces marxianus L3 and K. lactis MW98-8C strains were transformed and compared as hosts for the secretion. The effects of the media composition were evaluated:
In K. lactis, the highest volumetric activity was obtained in YKK synthetic medium in the presence of Cu2+/Zn2+ cofactors (9.6 kU l−1). In K. marxianus, active SOD was produced only in YPD medium supplemented with Cu2+ and Zn2+ (8.8 kU l−1). In order to improve the production of secreted active SOD in K. lactis, the SOD1 copper carrier (CCS1) was overexpressed and targeted to the secretory apparatus. A positive effect was observed
only when K. lactis was grown in a medium without Cu2+/Zn2+ supplement. The best performing culture conditions for K. lactis and K. marxianus recombinant strains were successfully applied to two laboratory-scale fed-batch processes, and volumetric SOD activities
increased up to 19.4 and 24.1 kU l−1, respectively. 相似文献
83.
Alberto Amaretti Stefano Raimondi Maurizio Sala Lucia Roncaglia Marzia De Lucia Alan Leonardi Maddalena Rossi 《Microbial cell factories》2010,9(1):73
Background
The production of microbial lipids has attracted considerable interest during the past decade since they can be successfully used to produce biodiesel by catalyzed transesterification with short chain alcohols. Certain yeast species, including several psychrophilic isolates, are oleaginous and accumulate lipids from 20 to 70% of biomass under appropriate cultivation conditions. Among them, Rhodotorula glacialis is a psychrophilic basidiomycetous species capable to accumulate intracellular lipids. 相似文献84.
Alessandra Corazza Enrico Rennella Paul Schanda Maria Chiara Mimmi Thomas Cutuil Sara Raimondi Sofia Giorgetti Federico Fogolari Paolo Viglino Lucio Frydman Maayan Gal Vittorio Bellotti Bernhard Brutscher Gennaro Esposito 《The Journal of biological chemistry》2010,285(8):5827-5835
β2-microglobulin (β2m), the light chain of class I major histocompatibility complex, is responsible for the dialysis-related amyloidosis and, in patients undergoing long term dialysis, the full-length and chemically unmodified β2m converts into amyloid fibrils. The protein, belonging to the immunoglobulin superfamily, in common to other members of this family, experiences during its folding a long-lived intermediate associated to the trans-to-cis isomerization of Pro-32 that has been addressed as the precursor of the amyloid fibril formation. In this respect, previous studies on the W60G β2m mutant, showing that the lack of Trp-60 prevents fibril formation in mild aggregating condition, prompted us to reinvestigate the refolding kinetics of wild type and W60G β2m at atomic resolution by real-time NMR. The analysis, conducted at ambient temperature by the band selective flip angle short transient real-time two-dimensional NMR techniques and probing the β2m states every 15 s, revealed a more complex folding energy landscape than previously reported for wild type β2m, involving more than a single intermediate species, and shedding new light into the fibrillogenic pathway. Moreover, a significant difference in the kinetic scheme previously characterized by optical spectroscopic methods was discovered for the W60G β2m mutant. 相似文献
85.
86.
87.
Corazza A Pettirossi F Viglino P Verdone G Garcia J Dumy P Giorgetti S Mangione P Raimondi S Stoppini M Bellotti V Esposito G 《The Journal of biological chemistry》2004,279(10):9176-9189
Three variants of human beta(2)-microglobulin (beta(2)-m) were compared with wild-type protein. For two variants, namely the mutant R3Abeta(2)-m and the form devoid of the N-terminal tripeptide (DeltaN3beta(2)-m), a reduced unfolding free energy was measured compared with wild-type beta(2)-m, whereas an increased stability was observed for the mutant H31Ybeta(2)-m. The solution structure could be determined by (1)H NMR spectroscopy and restrained modeling only for R3Abeta(2)-m that showed the same conformation as the parent species, except for deviations at the interstrand loops. Analogous conclusions were reached for H31Ybeta(2)-m and DeltaN3beta(2)-m. Precipitation and unfolding were observed over time periods shorter than 4-6 weeks with all the variants and, sometimes, with wild-type protein. The rate of structured protein loss from solution as a result of precipitation and unfolding always showed pseudo-zeroth order kinetics. This and the failure to observe an unfolded species without precipitation suggest that a nucleated conformational conversion scheme should apply for beta(2)-m fibrillogenesis. The mechanism is consistent with the previous and present results on beta(2)-m amyloid transition, provided a nucleated oligomeric species be considered the stable intermediate of fibrillogenesis, the monomeric intermediate being the necessary transition step along the pathway from the native protein to the nucleated oligomer. 相似文献
88.
Echlin-Bell DR Smith LL Li L Strissel PL Strick R Gupta V Banerjee J Larson R Relling MV Raimondi SC Hayashi Y Taki T Zeleznik-Le N Rowley JD 《Human genetics》2003,113(1):80-91
The MLL gene is involved in many chromosomal translocations leading to both acute myeloid and lymphoid leukemia. Some patients treated for primary malignancies with chemotherapeutic agents that inhibit DNA topoisomerase II (topo II) develop treatment-related leukemia (t-AML) caused by MLL gene rearrangement. Whether these patients are unusually susceptible to anti-topo II drugs, or whether this is a random adverse event is unknown. To discover genetic polymorphisms that may predispose patients to t-AML development, we sequenced the 8.3-kb MLL breakpoint cluster region (BCR) from 22 patients who had been treated with topo II inhibitors and who developed t-AML and from 37 patients who did not, and from eight infants and 20 normal individuals. Four polymorphic sites within Alu repetitive elements were identified; three affected the length of poly-A tracts and one altered the size of a trinucleotide repeat. The three poly-A tract polymorphisms occurred with equal frequency in leukemic patients and controls and hence are not predictors of risk. The trinucleotide GAA repeat has three alleles: (GAA)4, (GAA)5, and (GAA)6. The (GAA)6 allele is very rare. The adult t-AML patients are almost exclusively (GAA)4/5 heterozygotes (83%), whereas the normal population is only 55% (GAA)4/5 heterozygotic and is represented equally by (GAA)4 and (GAA)5 homozygotes (20% each). Only certain trends could be established because of the small sample size of these leukemic groups. Whereas adult t-AML patients are more likely to be (GAA)4/5 heterozygotes, this is not statistically significant, and this polymorphism within the MLL BCR has only a suggestive association with t-AML development. 相似文献
89.
Verotta L Lovaglio E Vidari G Finzi PV Neri MG Raimondi A Parapini S Taramelli D Riva A Bombardelli E 《Phytochemistry》2004,65(21):2867-2879
Supercritical CO2 selectively extracted a series of 4-alkyl and 4-phenyl 5,7-dihydroxycoumarins from Mesua ferrea blossoms. Chemical modifications of the isolated compounds allowed us to confirm the structures elucidated by spectroscopic means and to prepare new derivatives amenable to SAR studies and potential pharmaceutical development. Biological investigations towards the screening on a number of bacteria strains and Plasmodium falciparum, identified compounds 1-9 as weak antiprotozoal agents and potent antibacterials on resistant Gram-positive strains. 相似文献
90.
Bossi RT Aliverti A Raimondi D Fischer F Zanetti G Ferrari D Tahallah N Maier CS Heck AJ Rizzi M Mattevi A 《Biochemistry》2002,41(28):8807-8818
FprA is a mycobacterial oxidoreductase that catalyzes the transfer of reducing equivalents from NADPH to a protein acceptor. We determined the atomic resolution structure of FprA in the oxidized (1.05 A resolution) and NADPH-reduced (1.25 A resolution) forms. The comparison of these FprA structures with that of bovine adrenodoxin reductase showed no significant overall differences. Hence, these enzymes, which belong to the structural family of the disulfide oxidoreductases, are structurally conserved in very distant organisms such as mycobacteria and mammals. Despite the conservation of the overall fold, the details of the active site of FprA show some peculiar features. In the oxidized enzyme complex, the bound NADP+ exhibits a covalent modification, which has been identified as an oxygen atom linked through a carbonylic bond to the reactive C4 atom of the nicotinamide ring. Mass spectrometry has confirmed this assignment. This NADP+ derivative is likely to form by oxidation of the NADP+ adduct resulting from nucleophilic attack by an active-site water molecule. A Glu-His pair is well positioned to activate the attacking water through a mechanism analogous to that of the catalytic triad in serine proteases. The NADP+ nicotinamide ring exhibits the unusual cis conformation, which may favor derivative formation. The physiological significance of this reaction is presently unknown. However, it could assist with drug-design studies in that the modified NADP+ could serve as a lead compound for the development of specific inhibitors. 相似文献