Resolution and identification of the protein components of the photosystemII antenna system of higher plants by reversed-phase liquid chromatographywith electrospray-mass spectrometric detection

Reversed-phase liquid chromatography (RPLC) was interfaced to mass spectrom etry (MS) with an electrospray ion (ESI) source for the separation and accu rate molecular mass determination of the individual intrinsic membrane prot eins that comprise the photosystem II (PS II) major light-harvesting comple x (LHC II) and minor (CP24, CP26 and CP29) antenna system, whose molecular masses range between 22 000 and 29 000. PS LI is a supramolecular complex i ntrinsic of the thylacoid membrane, which plays the important role in photo synthesis of capturing solar energy, and transferring it to photochemical r eaction centers where energy conversion occurs. The protein components of t he PS II major and minor antenna systems were extracted from spinach thylac oid membranes and separated using a butyl-silica column eluted by an aceton itrile gradient in 0.05% (v/v) aqueous trifluoroacetic acid. On-line electr ospray MS allowed accurate molecular mass determination and identification of the protein components of PS II major and minor antenna system. The prop osed RPLC-ESI-MS method holds several advantages over sodium dodecyl sulfat e-polyacrylamide gel electrophoresis, the conventional technique for studyi ng membrane proteins, including a better protein separation, mass accuracy, speed and efficiency. (C) 2000 Elsevier Science B.V. All rights reserved.