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KL Britton HF Rogers Y Asano T Dairi Y Kato TJ Stillman DW Rice 《Acta crystallographica. Section D, Biological crystallography》1998,53(4):124-126
The novel NAD+-linked opine dehydrogenase from a soil isolate Arthrobacter sp. strain 1C belongs to an enzyme superfamily whose members exhibit quite diverse substrate specificites. Crystals of this opine dehydrogenase, obtained in the presence or absence of co-factor and substrates, have been shown to diffract to beyond 1.8 ? resolution. X-ray precession photographs have established that the crystals belong to space group P21212, with cell parameters a = 104.9, b = 80.0, c = 45.5 ? and a single subunit in the asymmetric unit. The elucidation of the three-dimensional structure of this enzyme will provide a structural framework for this novel class of dehydrogenases to enable a comparison to be made with other enzyme families and also as the basis for mutagenesis experiments directed towards the production of natural and synthetic opine-type compounds containing two chiral centres. 相似文献
2.
Simultaneous measurement of glucose and glutamine in aqueous solutions by near infrared spectroscopy 总被引:1,自引:0,他引:1
Hoeil Chung Mark A. Arnold Martin Rhiel David W. Murhammer 《Applied biochemistry and biotechnology》1995,50(2):109-125
A method is described for measuring the concentrations of both glucose and glutamine in binary mixtures from near infrared
(NIR) absorption spectra. Spectra are collected over the range from 5000–4000/cm (2.0–2.5μm) with a 1-mm optical path length.
Glucose absorbance features at 4710, 4400, and 4300/cm and glutamine features at 4700, 4580, and 4390/cm provide the analytical
information required for the measurement. Multivariate calibration models are generated by using partial least squares (PLS)
regression alone and PLS regression combined with a preprocessing digital Fourier filtering step. The ideal number of PLS
factors and spectral range are identified separately for each analyte. In addition, the optimum Fourier filter parameters
are established for both compounds. The best overall analytical performance is obtained by combining Fourier filtering and
PLS regression. Glucose measurements are established over the concentration range from 1.66–59.91 mM, with a standard error of prediction (SEP) of 0.32 mM and a mean percent error of 1.84%. Glutamine can be measured over the
concentration range from 1.10–30.65 mM with a SEP of 0.75 mM and a mean percent error of 6.67%. These results demonstrate
the analytical utility of NIR spectroscopy for monitoring glucose and glutamine levels in mammalian and insect cell cultures. 相似文献
3.
Zhang F Wolff MW Williams D Busch K Lang SC Murhammer DW Linhardt RJ 《Applied biochemistry and biotechnology》2001,90(2):125-136
Human secreted alkaline phosphatase (SEAP) was produced in a stablytransformed Spodoptera frugiperda Sf-9 insect cell line (Sfb4GalT) following infection with a recombinant Autographa californica multiple nuclear polyhedrovirus containing the SEAP gene under control of the polyhedrin promoter. An affinity chromatographic
column prepared by linking 4-aminobenzylphosphonic acid to histidyl-expoxy-Sepharose was used to isolate SEAP from the cell
supernatant following removal of cells and virus and 10-fold concentration through ultrafiltration. We found that the binding
of SEAP on the affinity matrix follows the Langmuir isotherm model. In addition, either recycling SEAP sample through the
column for 24 h or loading high SEAP concentrations resulted in a high-purity product. Some nonspecific binding of protein
on the matrix occurred when low concentrations of SEAP sample were loaded. Finally, we found that SEAP binding occurs rapidly,
i.e., within 30 min of adding the SEAP sample to the affinity matrix. 相似文献
4.
In this paper we discuss the recovery of derivatives and thecomputation of rigorous and useful upper bounds for the pointwiseerror in the recovered derivatives, for finite element approximationsof the Laplace equation with Neumann boundary conditions, especiallyat points close to or on a smooth, curved boundary. We analyzethe dipole image technique for the case of curved boundaries,and show how to compute reliable recovered derivatives and errorbounds even in the limiting case of points lying on the curvedboundary. Numerical experiments show reasonably tight errorbounds for points both close to and away from a curved boundary. 相似文献
5.
Wang Y Oberley LW Howe D Jarvis DL Chauhan G Murhammer DW 《Applied biochemistry and biotechnology》2004,119(2):181-193
It has previously been demonstrated that baculovirus infection of the Spodoptera frugiperda Sf-9 (Sf-9) and Trichoplusia ni BTI-Tn-5B1-4 (Tn-5B1-4) insect cell lines leads to oxidative stress as measured by protein and membrane lipid oxidation and
that this oxidative damage contributes to cell death. As a result of these findings, it was hypothesized that baculovirus
infection stimulates superoxide radical (O
2
·—
synthesis in the mitochondria and that the resulting O
2
·—
accumulation overwhelms the cells’ antioxidant defenses. We investigated the ability of manganese superoxide dismutase (MnSOD)
expression (which reduces O
2
·—
to H2O2) to overcome the oxidative damage caused by baculovirus infection. It was found that MnSOD expression significantly reduced
oxidative damage in baculovirus-infected Tn-5B1-4 cells but had no significant effect on oxidative damage in baculovirus-infected
Sf-9 cells. The results are consistent with the hypothesis that O
2
·—
accumulation in the mitochondria is at least partially responsible for the oxidative damage resulting from the baculovirus
infection of insect cells. 相似文献
6.
David W. Murhammer 《Applied biochemistry and biotechnology》1991,31(3):283-292
The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalian cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed. 相似文献
7.
Spear SK Rhiel M Murhammer DW Arnold MA 《Applied biochemistry and biotechnology》1998,75(2-3):175-186
A solid-state, diffuse reflectance-based fiberoptic sensor is described for quantifying ammonia. This sensor is constructed
by immobilizing chlorophenol red, a weak acid chromophoric indicator dye, in a microporous polypropylene membrane. A flow-injection
analysis system is used to carry a 10-μL aliquot of the sample across the treated membrane. Ammonia in the sample diffuses
through the air-filled pores within the membrane structure before reacting with the indicator dye. A reversible acid-base
reaction between ammonia and chlorophenol red results in a measurable change in the reflectance at 560 nm. Response characteristics
include a peak response within 20 s, a limit of detection of 0.2 ± 0.1 mM ammonia, and a dynamic range of up to 60 mM ammonia.
The analytical utility of this sensor is demonstrated by measuring ammonia levels in 48 individual samples collected during
the growth of PC3 human prostate cancer cells in a typical serum-containing growth medium. Accuracy of the proposed sensor
is verified by a comparison of results from this sensor to those from a conventional enzyme assay. 相似文献
8.
Secreted human alkaline phosphatase (SEAP, a model protein containing a single N-glycan chain) was expressed in Spodoptera frugiperda Sf-9 (Sf-9) and Trichoplusia ni BTI-Tn-5B1-4 (Tn-5B1-4) insect cell lines infected with recombinant Autographa californica multiple nuclear polyhedrovirus expressing SEAP under control of the polyhedrin promoter. SDS-PAGE showed that both systems
expressed fairly pure rSEAP products. The rSEAP expression level was 7.0 U/mL in Tn-5B1-4, higher than the 4.1 U/mL produced
by Sf-9. Kinetic analysis showed that V
max and K
m of human placental SEAP were approx 10-fold higher than that of rSEAP, whereas the V
max and K
m of rSEAP prepared using both insect cell lines were comparable. To characterize the recombinant SEAP (rSEAP) glycosylation,
the purified rSEAP was digested with PNGase F to release the N-glycan chains. Glycan analysis showed the presence of oligomannose-type N-linked glycans (i.e., Man2–8 GlcNAc2 and FucMan3 or 4GlcNAc2) in rSEAP from Sf9 and Tn-5B1-4 cell lines. The proportions of these oligosaccharide structures were different in the two
cell lines. Man4GlcNAc2 and FucMan4GlcNAc2 were the major rSEAP N-glycans produced in Sf-9 cells, while Man2GlcNAc2 was the major rSEAP N-glycan produced in Tn-5B1-4 cells. 相似文献
9.
David W. Murhammer 《Applied biochemistry and biotechnology》1996,59(2):199-220
This review discusses a number of issues relevant to the production and use of baculoviruses for pest control. Following this
review, patents pertaining to baculovirus use in pest control are summarized. 相似文献
10.
Review and patents and literature. The use of insect cell cultures for recombinant protein synthesis: Engineering aspects. 总被引:2,自引:0,他引:2
D W Murhammer 《Applied biochemistry and biotechnology》1991,31(3):283-310
The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalia cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed. 相似文献
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