CHANGE IN SULFHYDRYL GROUP MICROENVIRONMENT OF CALF LENS α‐CRYSTALLIN BY 300 nm LIGHT
CHANGE IN SULFHYDRYL GROUP MICROENVIRONMENT OF CALF LENS α‐CRYSTALLIN BY 300 nm LIGHT
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300 nm 光作用下小牛晶状体 α-晶状体蛋白巯基微环境的变化
DOI：
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发表时间：
1986
期刊：
影响因子：
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通讯作者：
L. Chylack
中科院分区：
文献类型：
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作者：
U. Andley;L. Chylack
摘要-使用特异性共价结合荧光巯基探针4-（N-碘乙酰氧基）乙基-N-甲氨基-7-正硝基苯-2-氧杂-1，3-二唑（IANBD）、N-碘乙酰基-N′-（5-磺基-1-萘基）乙二胺（1，5 IAEDANS）和5-碘乙酰胺荧光素（IAF）研究了300 nm辐照对小牛透镜α-晶状体蛋白巯基的影响。色氨酸荧光随α-晶状体蛋白的照射时间的降低伴随着疏水巯基标记IANBD的荧光的降低。此外，表面巯基标记IAF的荧光在辐照的α-晶状体蛋白中增加。这些结果表明，巯基基团是在一个更暴露（亲水性）的环境中的照射蛋白质比在控制，可能是因为部分解折叠的蛋白质。这一结果得到了IAEDANS荧光寿命测量的证实。IAEDANS-α-晶状体蛋白的衰减曲线的主要寿命为15.7 ns，次要寿命为24.6 ns。辐照后，主要组分的寿命降低到10.2 ns，次要组分的寿命降低到21.7 ns。变性IAEDANS-α-晶体蛋白的单次寿命为10.4 ns。这些结果表明，α-晶状体蛋白色氨酸残基的光诱导损伤改变了巯基的环境，并诱导蛋白质三级结构的变化。在蛋白质的三级结构中，半胱氨酸残基与色氨酸的接近性可能是它们对光诱导变化的敏感性的重要决定因素。
Abstract— The effect of 300 nm irradiation on the sulfhydryl groups of calf lens a‐crystallin has been investigated by using specific, covalently bound fluorescent sulfhydryl probes 4–(N‐iodoacetoxy)ethyl‐N‐methylamino‐7‐n‐itrobenz‐2‐o‐xa‐1,3‐d‐iazole (IANBD), N‐iodoacetyl‐N′‐(5‐s‐ulfo‐l‐naphthyl) ethylene‐diamine (1,5 IAEDANS) and 5‐i‐odoacetamidofluorescein (IAF). The decrease in tryptophan fluorescence with time of irradiation of a‐crystallin, is accompanied by a decrease in the fluorescence of the hydrophobic sulfhydryl label IANBD. In addition, the fluorescence of the surface‐sulfhydryl label IAF increased in the irradiated a‐crystallin. These results indicate that the sulfhydryl groups are in a more exposed (hydrophilic) environment in the irradiated protein than in the control, possibly because of partial unfolding of the protein. This result is confirmed by fluorescence lifetime measurements with IAEDANS. The decay curve of IAEDANS‐α‐crystallin has a major lifetime of 15.7 ns and a minor one of 24.6 ns. Upon irradiation, the lifetime of the major component decreases to 10.2 ns and that of the minor component to 21.7 ns. Denatured IAEDANS‐α‐crystallin has a single lifetime of 10.4 ns. These results show that the photoinduced damage to the tryptophan residues of α‐crystallin alters the environment of the sulfhydryl groups and induces a change in the tertiary structure of the protein. Proximity of the cysteine residues to tryptophan in the tertiary structure of the protein may be an important determinant of their susceptibility to photoinduced change.
(Na,K)-ATP 酶与荧光马来酰亚胺衍生物的反应。
DOI：
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发表时间：
1983
期刊：
The Journal of biological chemistry
影响因子：
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作者：
Gupte,SS;Lane,LK
通讯作者：
Lane,LK