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91.
Qingfeng Chen Corey S. Westfall Leslie M. Hicks Shiping Wang Joseph M. Jez 《The Journal of biological chemistry》2010,285(39):29780-29786
The GH3 family of acyl-acid-amido synthetases catalyze the ATP-dependent formation of amino acid conjugates to modulate levels of active plant hormones, including auxins and jasmonates. Initial biochemical studies of various GH3s show that these enzymes group into three families based on sequence relationships and acyl-acid substrate preference (I, jasmonate-conjugating; II, auxin- and salicylic acid-conjugating; III, benzoate-conjugating); however, little is known about the kinetic and chemical mechanisms of these enzymes. Here we use GH3-8 from Oryza sativa (rice; OsGH3-8), which functions as an indole-acetic acid (IAA)-amido synthetase, for detailed mechanistic studies. Steady-state kinetic analysis shows that the OsGH3-8 requires either Mg2+ or Mn2+ for maximal activity and is specific for aspartate but accepts asparagine as a substrate with a 45-fold decrease in catalytic efficiency and accepts other auxin analogs, including phenyl-acetic acid, indole butyric acid, and naphthalene-acetic acid, as acyl-acid substrates with 1.4–9-fold reductions in kcat/Km relative to IAA. Initial velocity and product inhibition studies indicate that the enzyme uses a Bi Uni Uni Bi Ping Pong reaction sequence. In the first half-reaction, ATP binds first followed by IAA. Next, formation of an adenylated IAA intermediate results in release of pyrophosphate. The second half-reaction begins with binding of aspartate, which reacts with the adenylated intermediate to release IAA-Asp and AMP. Formation of a catalytically competent adenylated-IAA reaction intermediate was confirmed by mass spectrometry. These mechanistic studies provide insight on the reaction catalyzed by the GH3 family of enzymes to modulate plant hormone action. 相似文献
92.
zge Karayel Francesca Tonelli Sebastian Virreira Winter Phillip E. Geyer Ying Fan Esther M. Sammler Dario R. Alessi Martin Steger Matthias Mann 《Molecular & cellular proteomics : MCP》2020,19(9):1546-1560
Highlights
- •MS-based clinical assay that accurately determines phospho Rab10 occupancy.
- •Stable isotope labeled phosphopeptide injected as a standard with endogenous tryptic phospho Rab peptide for accurate ratio determination.
- •Determination of pRab levels in neutrophils of Parkinson disease patients.
- •Relevance of pRab levels as marker of PD.
93.
Novel 2D van der Waals heterostructures with innovative bimetallic oxychloride (Bi‐ and Sb‐based oxychloride) nanosheets that are well dispersed on reduced graphene oxide nanosheets, are established through element engineering for superior potassium ion battery (PIBs) anodes. This material displays an exceptional electrochemical performance, obtaining a discharge capacity as high as 360 mAh g?1 at 100 mA g?1 after running 1000 cycles for over 9 months with a capacity preservation percentage of 88.5% and achieving a discharge capacity as high as 319 mAh g?1 at 1000 mA g?1, in addition to the low charge/discharge plateaus for anodes and promising full cell performance. More significantly, the nature of such 2D van der Waals heterostructures, including the element engineering for morphology control, the function of each component of heterostructures, the mechanism of potassium ion storage, and the process of K+ intercalation accompanied with the lattice distortion and chemical bond breakages, is explored in depth. This study is critical for not only paving the way for the practical application of PIBs but also shedding light on fundamentals of potassium ion storage in 2D van der Waals heterostructures. 相似文献
94.
Jian‐Yong Guo Yong‐Sheng Wang Tian Chen Xiao‐Xu Jiang Ping Wu Tao Geng Zhong‐Hua Pan Meng‐Ke Shang Cheng‐Xiang Hou Kun Gao Xi‐Jie Guo 《Insect Science》2020,27(3):449-462
Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) is a major pathogen of the economic insect silkworm, Bombyx mori. Virus‐encoded microRNAs (miRNAs) have been proven to play important roles in host–pathogen interactions. In this study we identified a BmCPV‐derived miRNA‐like 21 nt small RNA, BmCPV‐miR‐1, from the small RNA deep sequencing of BmCPV‐infected silkworm larvae by stem‐loop quantitative real‐time PCR (qPCR) and investigated its functions with qPCR and lentiviral expression systems. Bombyx mori inhibitor of apoptosis protein (BmIAP) gene was predicted by both target prediction software miRanda and Targetscan to be one of its target genes with a binding site for BmCPV‐miR‐1 at the 5′ untranslated region. It was found that the expression of BmCPV‐miR‐1 and its target gene BmIAP were both up‐regulated in BmCPV‐infected larvae. At the same time, it was confirmed that BmCPV‐miR‐1 could up‐regulate the expression of BmIAP gene in HEK293T cells with lentiviral expression systems and in BmN cells by transfecting mimics. Furthermore, BmCPV‐miR‐1 mimics could up‐regulate the expression level of BmIAP gene in midgut and fat body in the silkworm. In the midgut of BmCPV‐infected larvae, BmCPV‐miR‐1 mimics could be further up‐regulated and inhibitors could lower the virus‐mediated expression of BmIAP gene. With the viral genomic RNA segments S1 and S10 as indicators, BmCPV‐miR‐1 mimics could up‐regulate and inhibitors down‐regulate their replication in the infected silkworm. These results implied that BmCPV‐miR‐1 could inhibit cell apoptosis in the infected silkworm through up‐regulating BmIAP expression, providing the virus with a better cell circumstance for its replication. 相似文献
95.
96.
Secretion of Recombinant Pediocin PA-1 by Bifidobacterium longum, Using the Signal Sequence for Bifidobacterial α-Amylase 下载免费PDF全文
Gi-Seong Moon Yu-Ryang Pyun Myeong Soo Park Geun Eog Ji Wang June Kim 《Applied microbiology》2005,71(9):5630-5632
A recombinant DNA, encoding the chimeric protein of the signal sequence for bifidobacterial α-amylase mature pediocin PA-1, was introduced into Bifidobacterium longum MG1. Biologically active pediocin PA-1 was successfully secreted from the strain and showed bactericidal activity against Listeria monocytogenes and the same molecular mass as native pediocin PA-1. 相似文献
97.
The effects of dispersal limitation and topographic heterogeneity on beta diversity and phylobetadiversity in a subtropical forest 总被引:1,自引:0,他引:1
Yue Bin Zhigao Wang Zhangming Wang Wanhui Ye Honglin Cao Juyu Lian 《Plant Ecology》2010,209(2):237-256
We assessed the effects of topographic heterogeneity and stem density on species composition between grains of different sizes
(20 × 20, 50 × 50, and 100 × 100 m), based on partial Mantel tests. Similarity in species composition was measured by the
abundance-based Jaccard index (C_J) and by an index that incorporates phylogenetic information into C_J (pC_J). Plants were
divided into five groups, arbor, subarbor, and shrub according to life form and two other groups: species that produce dry
fruits (PDF) and that produce fleshy fruits (PFF). C_J and pC_J between any two grains at each grain size were calculated
separately for these groups and for all species combined. In order to examine what influences C_J and pC_J, we analyzed their
correlations with topographic heterogeneity variables and two dispersal limitation-related variables (stem and topographic
resistance). Our data indicate that at all three grain sizes, C_J and pC_J decrease with increasing distance for all plant
groups. Dispersal limitation and topographic heterogeneity were both important at 20 × 20 and 50 × 50 m grain sizes for C_J
and pC_J of all plant groups; and at 100 × 100 m grain size, topographic heterogeneity dominates over dispersal limitation
for some plant groups. C_J and pC_J of PDFs are less negatively correlated with stem resistance than those of PFFs. We conclude
that both beta diversity and phylobetadiversity are dependent on plant groups and grain sizes. 相似文献
98.
Zou Ya-Jie Wang He-Xiang Zhang Jin-Xia 《International journal of peptide research and therapeutics》2019,25(4):1389-1396
International Journal of Peptide Research and Therapeutics - A novel peroxidase has been isolated from fresh fruiting bodies of the mushroom Pleurotus pulmonarius, with a purification protocol of... 相似文献
99.
The study was designed to determine whether methionine-enkephalin (M-ENK) was present in the digestive system of the scallop
Chlamys farreri and investigate the effects of M-ENK on the activity of amylase, protease and lipase in the digestive system of C. farreri. The results indicated that M-ENK-like material was present in the epithelium and connective tissue of labial palps, mouth
labia, stomach, intestine, rectum, and hepatopancreas of the scallop C. farreri. Moreover, it was also found that many isolated small cells showing M-ENK-like immunoreactivity were scattered in the epithelial
layer of intestine, and many isolated big epithelial cells showing M-ENK-like immunoreactivity were scattered in tubules of
hepatopancreas of the scallop. The activity levels of amylase and lipase in crystalline style, hepatopancreas and intestine
were enhanced at 1 h after injection of exogenous M-ENK into adductor muscle of the scallops, whereas protease activity levels
were significantly suppressed. Our report constitutes the first characterization of M-ENK in the digestive system of scallop
C. farreri and investigates the effects of M-ENK on the activities of digestive enzymes of mollusk for the first time. The results suggest
an involvement of M-ENK in the functional regulation of the digestive system of C. farreri. 相似文献
100.