Endogenous substrates of transglutaminase (TGase; EC 2.3.2.13) have been identified in choloroplasts of Helianthus tuberosus leaves. The activity of TGase is Ca2+- and light-stimulated and catalyzes the incorporation of polyamines into thylakoid and stromal proteins. These proteins were separated by two-dimensional gel electrophoresis (first dimension: Deriphat-PAGE; second dimension: SDS-urea-PAGE) and Western-blotted. The thylakoid proteins were recognized by polyclonal antibodies as apoproteins of the chlorophyll-a/b antenna complex (LHCII, CP24, CP26 and CP29); a stromal protein was recognized by antibodies as the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. A possible localization of the acyl donor site for CP26 is proposed. A comparative analysis of polyamine incorporation into trichloroacetic-acid-precipitable material indicated that spermidine was a preferential acyl-acceptor substrate with respect to putrescine, even though the above-reported substrates are the same. The nature of the substrates, together with the light stimulation, support the working hypothesis of a possible role of TGase in regulating the light-harvesting function. © 1994 Springer-Verlag.
Del Duca S., Tidu V., Bassi R., Esposito C., Serafini-Fracassini D. (1994). Identification of chlorophyll-a/b proteins as substrates of transglutaminase activity in isolated chloroplasts of Helianthus tuberosus L. PLANTA, 193(2), 283-289 [10.1007/BF00192542].
Identification of chlorophyll-a/b proteins as substrates of transglutaminase activity in isolated chloroplasts of Helianthus tuberosus L
Del Duca S.;Serafini-Fracassini D.
1994
Abstract
Endogenous substrates of transglutaminase (TGase; EC 2.3.2.13) have been identified in choloroplasts of Helianthus tuberosus leaves. The activity of TGase is Ca2+- and light-stimulated and catalyzes the incorporation of polyamines into thylakoid and stromal proteins. These proteins were separated by two-dimensional gel electrophoresis (first dimension: Deriphat-PAGE; second dimension: SDS-urea-PAGE) and Western-blotted. The thylakoid proteins were recognized by polyclonal antibodies as apoproteins of the chlorophyll-a/b antenna complex (LHCII, CP24, CP26 and CP29); a stromal protein was recognized by antibodies as the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. A possible localization of the acyl donor site for CP26 is proposed. A comparative analysis of polyamine incorporation into trichloroacetic-acid-precipitable material indicated that spermidine was a preferential acyl-acceptor substrate with respect to putrescine, even though the above-reported substrates are the same. The nature of the substrates, together with the light stimulation, support the working hypothesis of a possible role of TGase in regulating the light-harvesting function. © 1994 Springer-Verlag.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
