CHLOROPHYLL BIOSYNTHESIS AND ASSEMBLY INTO CHLOROPHYLL PROTEIN COMPLEXES IN ISOLATED DEVELOPING CHLOROPLASTS
CHLOROPHYLL BIOSYNTHESIS AND ASSEMBLY INTO CHLOROPHYLL PROTEIN COMPLEXES IN ISOLATED DEVELOPING CHLOROPLASTS
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DOI：
10.1073/pnas.82.16.5370
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发表时间：
1985-01-01
影响因子：
11.1
通讯作者：
CASTELFRANCO, PA
中科院分区：
文献类型：
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作者：
BHAYA, D;CASTELFRANCO, PA
从绿色黄瓜子叶或光周期生长的豌豆幼苗中分离出发育中的质体，将14C标记的5-氨基乙酰丙酸(ALA)掺入叶绿素(Chl)中。掺入是光依赖的，被S-腺苷蛋氨酸增强，并线性地作用1小时。ALA体外合成Chl的速率与体内积累Chl的速率相当。乙酰丙酸和二氧庚酸对叶绿素合成有强烈的抑制作用，但对叶绿体蛋白质的合成无明显抑制作用。氯霉素和壮观霉素都不影响Chl的合成，但蛋白质的合成受到强烈的抑制。用[14C]Ala孵育的叶绿体的类囊体膜组分通过电泳法分离，然后进行放射自显影术。这项工作表明：(1)新合成的Chl被组装成Chl-蛋白质复合体，(Ii)孵育过程中抑制蛋白质合成不会改变标记模式。因此，在分离的质体中叶绿素的合成(来自ALA)和膜蛋白的合成之间没有可观察到的短期协同调节。
Isolated developing plastids from greening cucumber cotyledons or from photoperiodically grown pea seedlings incorporated 14C-labeled 5-aminolevulinic acid (ALA) into chlorophyll (Chl). Incorporation was light dependent, enhanced by S-adenosylmethionine, and linear for 1 hr. The in vitro rate of Chl synthesis from ALA was comparable to the in vivo rate of Chl accumulation. Levulinic acid and dioxoheptanoic acid strongly inhibited Chl synthesis but not plastid protein synthesis. Neither chloramphenicol nor spectinomycin affected Chl synthesis, although protein synthesis was strongly inhibited. Components of thylakoid membranes from plastids incubated with [14C]ALA were resolved by electrophoresis and then subjectd to autoradiography. This work showed that (i) newly synthesized Chl was assembled into Chl-protein complexes and (ii) the inhibition of protein synthesis during the incubation did not alter the labeling pattern. Thus, there was no observable short-term coregulation between Chl synthesis (from ALA) and the synthesis of membrane proteins in isolated plastids.