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Biomedical subjects

M Sigrist

Publications and source records attributed to M Sigrist.

At least 37 records · Page 2Linked to original sources
PubMed1994

Appearance of type 1, 2, and 3 light-harvesting complex II and light-harvesting complex I proteins during light-induced greening of barley (Hordeum vulgare) etioplasts.

Monospecific antibodies directed against typical domains of type 1, 2, and 3 light-harvesting complex (LHC) II apoproteins have been used (a) to identify these apoproteins on denaturing sodium dodecyl sulfate gels of barley (Hordeum vulgare) thylakoids, (b) to determine their distribution between grana and stroma membranes, and (c) to follow their accumulation during light-induced greening of etioplasts. In addition, we have studied the light-induced assembly of chlorophyll-protein complexes with a native green gel system (K.D. Allen, L.A. Staehelin [1991] Anal Biochem 194: 214-222). Western blot analysis of the three major LHCII apoprotein bands has identified the highest molecular mass band at 27.5 kD as containing the type 2 LHCII apoproteins, the middle band at 26.9 kD as containing the type 1 LHCII apoproteins, and the lowest band at 26.0 kD as containing the type 3 LHCII apoproteins. During light-induced greening of 6-d-old etiolated barley seedlings, the type 1, 2, and 3 LHCII apoproteins accumulate simultaneously and at similar rates but appear somewhat sooner (< 4 h) in thylakoids from apical than from basal (4-8 h) leaf segments. LHCI polypeptides accrue with similar kinetics, whereas the 33-kD oxygen-evolving complex polypeptides can be detected already in the 0-h light samples. During the most rapid phase of thylakoid development (8-24 h), two slightly larger (28.3 and 28.7 kD) type 2 LHCII apoproteins (precursor intermediates?) also accumulate in the thylakoids. No corresponding higher molecular mass forms of type 1 and 3 LHCII apoproteins could be detected. It is interesting that differences are still apparent in the composition of chlorophyll-protein complexes of light-control plants and those of etiolated plants greened for 8 d.

Amino Acid Sequence↗
PubMed1992

Identification of type 1 and type 2 light-harvesting chlorophyll a/b-binding proteins using monospecific antibodies.

The amino acid sequences of more than 40 apoproteins of the light-harvesting complex associated with Photosystem II (LHC II) of various plants have been deduced by sequencing their corresponding genes. These highly conserved sequences fall into two major categories, type 1 and type 2, that differ mainly in a small number of domains close to the N-terminus. We have made polyclonal, monospecific antibodies against synthetic peptides corresponding to the most unique sequence domains of the N-terminal regions of type 1 and type 2 LHC II apoproteins, using sequences derived from petunia genes. On Western blots our anti-type 1 and 2 antibodies crossreact with light-harvesting proteins of petunia, tomato, spinach and several other plants. By using a new gel-system based on ammediol (2-amino-2-methyl-1,3-propanediol), we are able to resolve up to eight LHC II apoproteins. On petunia, tomato and spinach blots the anti type 1 antibodies bind to two or more of the higher molecular weight LHC II polypeptides, whereas the anti type 2 antibodies recognize very specifically only one or two of the lower molecular weight LHC-proteins. In all plants studied, the type 1 LHC II apoproteins are more numerous and span a greater size range than the type 2 apoproteins. This is consistent with the smaller number of type 2 LHC II CAB genes that have been discovered to date.

Amino Acid Sequence↗