Impact of two-bond 15N–15N scalar couplings on 15N transverse relaxation measurements for arginine side chains of proteins
Sign Up to like & getrecommendations! Published in 2018 at "Journal of Biomolecular NMR"
DOI: 10.1007/s10858-018-0189-y
Abstract: NMR relaxation of arginine (Arg) 15Nε nuclei is useful for studying side-chain dynamics of proteins. In this work, we studied the impact of two geminal 15N–15N scalar couplings on measurements of transverse relaxation rates (R2)… read more here.
Keywords: side chains; relaxation; 15n 15n; 15n nuclei ... See more keywords
Responses and Indications of Foliar Nitrogen Contents and δ15N values to Atmospheric Nitrogen Deposition in Beijing, China
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DOI: 10.5846/stxb201511202348
Abstract: 为探究植物对大气氮沉降的响应和对这部分氮素的来源指示作用，本研究通过对北京地区198个采样点，典型落叶阔叶乔木杨属（Populus）和柳属（Salix）植物叶片进行采样，测定其叶片样品含氮量和δ15 N值。结果表明：北京地区杨属植物叶片含氮量为16.5-38.6 g/kg，平均（24.0±4.0）g/kg；柳属植物叶片含氮量为17.2-36.2 g/kg，平均（25.9±4.1）g/kg。研究区域范围内杨属、柳属植物叶片的含氮量均呈现出西北低、东南高的对角线型分布，与该区域大气氮沉降的空间变异相吻合。由于研究区域范围内气候因子无明显的变异，植物叶片的含氮量变化反应了大气氮沉降对植物元素化学计量特征的影响和植物对大气氮沉降的响应。北京地区杨属植物叶片δ15N值为-3.95‰-8.10‰，平均（1.15±2.48）‰；柳属植物叶片δ15N值为-3.04‰-9.73‰，平均（2.31±2.60）‰。杨属和柳属植物叶片的δ15N值均呈现出西北高、中部高、东南低的空间分布，与叶片含氮量空间分布趋势相反。中部城区较高的δ15N值反应了交通污染对大气含氮化合物增加的影响；西北部较高的δ15N值反应了该区域受人为活动排放源的影响较少，自然的氮循环是其较高δ15N值的主要原因；东南部较低的δ15N值则有可能是由农业活动和交通共同作用的结果。 read more here.
Keywords: 15n 15n; nitrogen contents; responses indications; indications foliar ... See more keywords