On the nature and possible functions of the 673- and 684-mμ forms in vivo of chlorophyll

Sironval, C.; Michel-Wolwertz, M.-R.; Madsen, Axel

doi:10.1016/0926-6585(65)90043-9

Cited by 70 publications

(21 citation statements)

References 15 publications

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“…The shift to Chl 684 and the phytylation (18,22) accompanying the Chl 684 to C 673 shift appear to be eliminated by disruption of the organized structure of the plastid. The report that Chl 684 was form-ed from PChl 650 in barley leaf homogenates (5) indicates the dark reaction might be studied in isolated proplastids.…”

Section: Discussionmentioning

confidence: 99%

A Short-lived Intermediate Form in the in Vivo Conversion of Protochlorophyllide 650 to Chlorophyllide 684

Bonner

1969

Plant Physiol.

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A bstract. When dark-grown leaves of Phaseolus vulgar-is, Hordeucm vulgare, Zea mays and Pisum sativum were irradiated for 3 sec at 20 the first product of protochlorophyllide 650 conversion had an absorption maximum at 678 nm. This form was then converted in a dark reaction to chlorophyllide 684, the form generally observed and regarded as the in vivo product of the photoreaction. The dark conversion at 20 was complete in 6 to 10 min in the various plants. The time course of the dark reaction was followed at 690 nm near the maximum of the difference spectrum for the conversion. There was a oonstant relationship between the initial amount of chlorophyllide 678 and the final amount of chlorophyllide 684. The rates of the dark reaction at 20 varied 3-fold among the plants treated. The reaction was not first order. At 250 the reaction followed at 690 nm was complete in 20 to 60 sec. Ql0's varied from 2.8 to 3.7 between 20 and 25°. Phytochrome absorbancy changes were shown to be too low to interfere with these measurements except in pea leaves. In a subsequent stage of greening newly regenerated protochlorophyllide went through the same sequence upon photoconversion. Chlorophyllide 678 probably corresponds to the product formed in vitro from the protochlorophyllide holochrome. The dark reaction appears to represent the first interaction between the photoconverted holochrome and other elements of the proplastid. The lack of this dark reaction could also account for the spectral properties of certain albino mutants.The photochemical conversion of protochlorophyllide to chlorophyllide in intact leaves has been reported to involve the conversion of a 650 nm absorbing protochlorophyllide form (Pchl 650) to a chlorophvllide formi with a peak at about 684 (Chl 684) (5,17,19). The Chl 684 is considered to be the product of the photochemical conversion in vizvo. On the other hand several bits of evidence indicate that the first product of the photoconversion of the isolated protochlorophyllide holochrome absorbs from 678 to 680 nim. Smith et al. (20) reported the initial absorption maximum of newly formed chlorophyllide was about 680 nm but that as the holochrome was processed the peaks of both the protochlorophyllide and chlorophvllide product gradually shifted to shorter wxavelengths. Boardman (2, p 463) in a reference to unpublished work, 1963, indicated that the initial product of the photoconversion of the isolated holochrome from beans absorbed at 680 to 682 nm but shortly shifted to a 675 nm peak. Schopfer and Siegelman (015) report a 6/78 nm maximum for the initial product in a purified system. Butler and Briggs (5) noted that in crude barley extracts the product peaked at 685 nm. It is the purpose of this paper to present data showing in all 4 species examined that the photoreaction in chlorophyll synthesis in vizo involves a conversion of protochlorophyllide 650 to chlorophyllide absorbing at 678 to 679 nm which is then converted to chlorophyllide 684 (Chl 684) in a dark, thermal reaction. This reaction precedes t...

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Section: Discussionmentioning

confidence: 99%

A Short-lived Intermediate Form in the in Vivo Conversion of Protochlorophyllide 650 to Chlorophyllide 684

Bonner

1969

Plant Physiol.

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“…This hypothesis is supported by the demonstration that the shift also occurs in isolated Chle-holochrome suspensions (3,14,26), and other recent evidence indicates that a change in holochrome conformation occurs during the shift (14,22,27). An alternative view is that phytylation is the cause of the Shibata shift (29) but there is little direct experimental support for this view.The rate of the Shibata shift is variable and appears to depend on several parameters. Electron microscopical studies have indicated that the shift is itself correlated with specific membrane changes occurring in the developing plastid; according to Von Wettstein's group, prolamellar body dispersal can occur simultaneously with the Shibata shift in barley but they add that in other species the relationship between the spectral and ultrastructural changes is not always as clearly seen (13, 43).…”

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confidence: 96%

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confidence: 96%

The Effect of Adenosine 5′-Triphosphate on the Shibata Shift and on Associated Structural Changes in the Conformation of the Prolamellar Body in Isolated Maize Etioplasts

Horton

Leech²

1975

Plant Physiol.

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Isolated maize (Zea mays var. kelvedon glory) etioplasts have been used to investigate the relationships between the spectral shifts and ultrastructural changes which occur during light-induced chloroplast development. After primary photoconversion, the Shibata shift was observed as a change from 680 to 670 nm in the chlorophyllide absorption maximum. When 1.5 nM ATP was added to the incubation medium the maximum was 675 nm even after 3.5 hours of illumination. Difference spectra for this effect indicate ATP inhibition of the Shibata shift. Two bands with maxima at 682 and 669 nm can be used to fit spectra of both ATP-treated and control etioplasts, the estimated proportions of chlorophyllide 682 being 36% and 6%, respectively. Quantitative analysis of electron micrographs of the etioplasts showed that the frequency of untransformed prolameliar bodies was also higher in the presence of ATP (73% untransformed compared to 22% in the absence of ATP). A similar correlation was observed when transformation was measured for two etioplast fractions which show the shift to different extents. These results imply that the Shibata shift and prolamellar body transformation are related events, both being inhibited by the presence of ATP. ATP may therefore have an important role in regulating the early stages of plastid development.The early stages of the light-induced transformation of greening etioplasts into chloroplasts in leaves involve several shifts in the position of the chlorophyll(ide) absorption maximum (1,8,11,18,28,(30)(31)(32) (8,12), suggesting that the changes in association between different pigment molecules or between pigment molecules and other membrane components is the cause of the shift (18). This hypothesis is supported by the demonstration that the shift also occurs in isolated Chle-holochrome suspensions (3,14,26), and other recent evidence indicates that a change in holochrome conformation occurs during the shift (14,22,27). An alternative view is that phytylation is the cause of the Shibata shift (29) but there is little direct experimental support for this view.The rate of the Shibata shift is variable and appears to depend on several parameters. Electron microscopical studies have indicated that the shift is itself correlated with specific membrane changes occurring in the developing plastid; according to Von Wettstein's group, prolamellar body dispersal can occur simultaneously with the Shibata shift in barley but they add that in other species the relationship between the spectral and ultrastructural changes is not always as clearly seen (13, 43).Studies using whole plants in which attempts have been made to examine the control of the Shibata shift and its relationship to membrane changes have been hindered by the complexity of the metabolism of the intact tissue and by the difficulty in inducing alteration of specific processes from outside the whole organism. Recently systems of isolated etioplasts have been described by Wellburn and Wellburn (40,41,42) and by Horton and Leech (15,16)

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“…Although several proposals, such as pigment aggregation (5,21), esterification (25), or association with a specific type of membrane (19), have been put forward to account for these different Chlide complexes and their interconversions, no generally accepted explanation for the phenomena has emerged.…”

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confidence: 99%

Pigment-Protein Complexes of Illuminated Etiolated Leaves

Oliver¹,

Griffiths²

1982

Plant Physiol.

127

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On the nature and possible functions of the 673- and 684-mμ forms in vivo of chlorophyll

Cited by 70 publications

References 15 publications

A Short-lived Intermediate Form in the in Vivo Conversion of Protochlorophyllide 650 to Chlorophyllide 684

A Short-lived Intermediate Form in the in Vivo Conversion of Protochlorophyllide 650 to Chlorophyllide 684

The Effect of Adenosine 5′-Triphosphate on the Shibata Shift and on Associated Structural Changes in the Conformation of the Prolamellar Body in Isolated Maize Etioplasts

Pigment-Protein Complexes of Illuminated Etiolated Leaves

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