Chlorina
 and viridis
 mutants of barley (Hordeum vulgare
 L.) allow assignment of long-wavelength chlorophyll forms to individual Lhca proteins of photosystem I in vivo

The in vivo biosynthesis of the P700 chlorophyll a-apoprotein was examined to determine whether this process is light regulated and to determine its relationship to chlorophyll accumulation during light-induced chloroplast development in barley (Hordeum vulgare L.). Rabbit antibodies to the 58,000-62,000-mol-wt apoprotein were used to measure relative synthesis rates by immunoprecipitation of in vivo labeled leaf proteins and to detect apoprotein accumulation on nitrocellulose protein blots. 5-d-old, dark-grown barley seedlings did not contain, or show net synthesis of, the 58,000-62,000-mol-wt polypeptide. When dark-grown barley seedlings were illuminated, net synthesis of the apoprotein was observed within the first 15 min of illumination and accumulated apoprotein was measurable after 1 h. After 4 h, P700 chlorophyll a-apoprotein biosynthesis accounted for up to 10% of the total cellular membrane protein synthesis. Changes in the rate of synthesis during chloroplast development suggest coordination between production of the 58,000-62,000-mol-wt polypeptide and the accumulation of chlorophyll. However, when plants were returned to darkness after a period of illumination (4 h) P700 chlorophyll a-apoprotein synthesis continued for a period of hours though at a reduced rate. Thus we found that neither illumination nor the rate of chlorophyll synthesis directly control the rate of apoprotein synthesis. The rapidity of the light-induced change in net synthesis of the apoprotein indicates that this response is tightly coupled to the primary events of light-induced chloroplast development. The data also demonstrate that de novo synthesis of the apoprotein is required for the onset of photosystem I activity in greening seedlings.

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Inositol phosphates in barley (Hordeum vulgare L.) aleurone tissue are stereochemically similar to the products of breakdown of InsP6in vitro by wheat-bran phytase

Biochemical Journal ◽

10.1042/bj3180279 ◽

1996 ◽

Vol 318 (1) ◽

pp. 279-286 ◽

Cited By ~ 27

Author(s):

Charles A BREARLEY ◽

David E HANKE

Keyword(s):

Hordeum Vulgare ◽

Wheat Bran ◽

Hplc Analysis ◽

Inositol Phosphates ◽

Hordeum Vulgare L ◽

Inositol Pyrophosphate ◽

Barley Aleurone ◽

Aleurone Tissue

Partisphere SAX HPLC analysis of endogenous inositol phosphates in [3H]inositol-labelled barley aleurone tissue revealed a range of isomers, including d- and/or l-Ins3P, d- and/or l-Ins(1,4)P2, d- and/or l-Ins(1,2)P2, a third unidentified InsP2, Ins(1,2,3)P3, d- and/or l-Ins(1,2,6)P3, d-and/or l-Ins(1,2,3,4)P4, d- and/or l-Ins(1,2,5,6)P4, Ins(1,3,4,5,6)P5, d- and/or l-Ins(1,2,3,4,5)P5, Ins(1,2,3,4,6)P5, InsP6 and a molecule with the chromatographic properties of an inositol pyrophosphate. The striking match between the identities of the stereoisomers, and in some cases enantiomers, detected in vivo and those stereoisomers produced in vitro by the action of wheat-bran phytase on InsP6 [Cosgrove (1980) Inositol Phosphates: Their Chemistry, Biochemistry and Physiology, Elsevier, Amsterdam] strongly suggests that most of the inositol phosphates identified are products of the breakdown of InsP6 by endogenous phytase(s) with stereospecificity similar to that of the wheat-bran enzyme(s).

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Carotenoid Triplet States Associated with the Long-Wavelength-Emitting Chlorophyll Forms of Photosystem I in Isolated Thylakoid Membranes

The Journal of Physical Chemistry B ◽

10.1021/jp047077k ◽

2005 ◽

Vol 109 (2) ◽

pp. 986-991 ◽

Cited By ~ 10

Author(s):

Stefano Santabarbara ◽

Donatella Carbonera

Keyword(s):

Photosystem I ◽

Thylakoid Membranes ◽

Triplet States ◽

Long Wavelength ◽

Chlorophyll Forms

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