THE ROLE OF SEPARATE MOLECULAR DOMAINS IN THE STRUCTURE OF PHYTOCHROME FROM ETIOLATED AVENA-SATIVA L
THE ROLE OF SEPARATE MOLECULAR DOMAINS IN THE STRUCTURE OF PHYTOCHROME FROM ETIOLATED AVENA-SATIVA L
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DOI：
10.1007/bf00395966
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发表时间：
1985-01-01
期刊：
影响因子：
4.3
通讯作者：
QUAIL, P
中科院分区：
文献类型：
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作者：
JONES, AM;VIERSTRA, RD;QUAIL, P
研究了内源性蛋白酶作用下黄化燕麦光敏色素（124-kDa（kilodalton））产生的肽的光谱特性，以评估氨基端和羧基端结构域在维持蛋白质和发色团之间适当相互作用中的作用。氨基末端的74 kDa色肽是色素（Pfr）的远红吸收形式的降解产物，在光谱上与124 kDa未降解分子相似。差谱（Pr-Pfr）的最小值和最大值分别为730和665 nm，光谱变化率为1。此外，像未降解的124-kDa光敏色素一样，74-kDa肽表现出最小的暗回复。多肽的55 kDa羧基末端的一半不与发色团相互作用，并且可能在氨基末端结构域的结构完整性中不起作用。64-kDa的chromopeptide可以产生直接从74-kDa的物种裂解10 kDa的氨基末端孵育后，这一物种的Pr。伴随着这种转换是光谱特性的变化，即，在差异光谱最小值的移动到722-724 nm和10倍增加的能力为黑暗逆转。6-10 kDa的氨基末端片段继续发挥其在74-kDa肽中维持适当的色素团-蛋白质相互作用的作用，就像它在未降解分子中一样。相反，在蛋白水解为64-kDa物质时去除该片段导致异常光谱特性，类似于当该结构域从全长124-kDa分子中丢失时观察到的那些，导致118/114-kDa降解产物。光转换的74-kDa的chromopeptide从PFR到Pr暴露蛋白水解敏感位点在相同的方式在124-kDa的分子。分离的，74 kDa的氨基末端结构域经历了光诱导的构象变化，在完整的分子。
The spectral properties of peptides generated from etiolated Avena, 124-kDa (kilodalton) phytochrome by endogenous protease(s) were studied to assess the role of the amino-terminal and the carboxyl-terminal domains in maintaining the proper interaction between protein and chromophore. The amino-terminal, 74-kDa chromopeptide, a degradation product of the far-red absorbing form of the pigment (Pfr), is spectrally similar to the 124-kDa, undegraded molecule. The minimum and maximum of the difference spectrum (Pr-Pfr) are 730 and 665 nm, respectively, and the spectral-change ratio is unity. Also, like undegraded, 124-kDa phytochrome, the 74-kDa peptide exhibits minimal dark reversion. The 55-kDa, carboxyl-terminal half of the polypeptide does not interact with the chromophore and may not have a role in the structural integrity of the amino-terminal domain. The 64-kDa chromopeptide can be generated directly from the 74-kDa species by cleavage of 10 kDa from the amino terminus upon incubation of this species as Pr. Accompanying this conversion are changes in the spectral properties, namely, a shift in the difference spectrum minimum to 722-724 nm and a 10-fold increase in the capacity for dark reversion. The 6-10 kDa, amino-terminal segment continues to function in its role of maintaining proper chromatophore-protein interactions in the 74-kDa peptide as it does in the undegraded molecule. Conversely, removal of this segment upon proteolysis to the 64-kDa species leads to aberrant spectral properties analogous to those observed when this domain is lost from the full-length, 124-kDa molecule, resulting in the 118/114-kDa degradation products. Photoconversion of the 74-kDa chromopeptide from Pfr to Pr exposes proteolytically susceptible sites in the same way as in the 124-kDa molecule. The separated, 74-kDa amino-terminal domain undergoes a photoinducible conformational change comparable to that in the intact molecule.