3Faculty of Medicine, University of Latvia, Sarlotes 1a, Riga LV1001, Latvia
4Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga LV 1006, Latvia
* To whom correspondence should be addressed.
Received February 29, 2012; Revision received March 11, 2012
The tightly bound proteins (TBPs), a protein group that remains attached to DNA either covalently or noncovalently after deproteinization, have been found in numerous eukaryotic species. Some TBPs isolated from mammalian and yeast cells possess phosphatase or kinase activity. The aim of this study was to characterize further TBPs in barley (Hordeum vulgare) cells. The spectra of TBPs varied in different organs of barley shoots (first leaves, coleoptile, and roots) and at different developmental stages of the plant. Some barley TBPs manifested phosphatase, probably Ser/Thr or dual Ser/Thr/Tyr activity. MALDI-TOF mass spectrometry of barley TBPs identified several proteins involved in chromatin rearrangement and regulation processes, including transcription factors, serpins, protein phosphatases and protein kinases, RNA helicases, and DNA topoisomerase II.
KEY WORDS: tightly bound proteins, nuclear matrix, phosphatase