大麦突变种Chlorina-f 2类囊体膜的叶绿素蛋白复合体

当突变种大麦Chlorina-f 2的类囊体膜在SDS/叶绿素的重量比为10:1,叶绿素的浓度为0.5mg/ml的条件下增溶,并在SDS-聚丙烯酰胺凝胶电泳中进行分离时,共出现4条含叶绿素的带。按电泳迁移率的增加,这些带分别是CP Ⅰ,CPa 1,CPa 2和FC。光谱测定表明CP Ⅰ为混有少量光系统Ⅱ??成分的光系统Ⅰ反应中心复合体,CPa 2为光系统Ⅱ反应中心复合体,CPa 2为光系统Ⅱ内周天线复合体。属于光系统Ⅰ的CP Ⅰ的叶绿素含量占总叶绿素的45.6%,而属于光系统Ⅱ的CPa Ⅰ和CPa 2的叶绿素之和则占总叶绿素的43.2%。可见在缺b大麦中,两个都失缺其外周天线的光系统的叶绿素含量是基本相等的。这和光合作用中两个光反应相互串联的理论是完全一致的。

CHLOROPHYLL-PROTEIN COMPLEXES OF THYLAKOID MEMBRANES FROM A MUTANT BARLEY CHLORINA-F2

Four chlorophyll-containing zones wereresolved from mutant barley Chlorina-f2 thy-lakoid membranes after membranes were so-lubilized by SDS in a final SDS/Chl weightratio 10/1 and Chl conc,at 0.5 mg Chl/ml,and subjected to discontinuous SDS-PAGE.The 4 resolved zones in order of increasingmobility were designated as CPI,CPa1,CPa2and FC. The absorption spectrum of CPI had ared maximum at 676 nm and a peak in theblue at 436 nm.It was identified as PS-Ichlorophyll-protein complex without its peri-peral antenna LHC-I,but was contaminatedwith minor PS-II which was implied by theappearance of fluorescence emission peak at685 nm besides the main one at 720 nm. CPa1 and CPa 2 had the same absorptionmaximal in the blue region at 436 nm,butthey had different absorption peaks in the redat 672 and 670 nm,respectively.The fluo-rescence emission of CPal and CPa 2 had thesame peak at 685 nm at 77 K indicating thatthey belonged to PS-II. It was calculated that 45.6% chloro-phyll in thylakoid membranes of Chlorina-f 2resided in PS-I,while 43.2% in PS-II.Thedifference of chlorophyll contents betweenPS-I and PS-II was only 2.4%.Concerningthe fact that minor PS-II compound remainedin the part of PS-I zones,it concluded thatthe distribution of chlorophyll molecules inPS-I and PS-II (both of them lack their pe-ripheral antennae) of chlorophyll b-less mu-tant barley was equal.This result was inagreement on the theory of the operation ofPS-I and PS-II in series in photosynthesis.