Substitution of isoleucine L177 by histidine in Rhodobacter sphaeroides reaction center results in the covalent binding of PA bacteriochlorophyll to the L subunit.
In this work, we report the unique case of bacteriochlorophyll (BChl) - protein covalent attachment in a photosynthetic membrane complex caused by a single mutation. The isoleucine L177 was substituted by histidine in the photosynthetic reaction center (RC) of Rhodobacter sphaeroides. Pigment analysis revealed that one BChl molecule was missing in the acetone-methanol extract of the I(L177)H RCs. SDS-PAGE demonstrated that this BChl molecule could not be extracted with organic solvents apparently because of its stable covalent attachment to the mutant RC L-subunit. Our data indicate that the attached bacteriochlorophyll is one of the special pair BChls, P(A). The chemical nature of this covalent interaction remains to be identified.
Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russia.
Tatiana Y
TY
Fufina
Lyudmila G
LG
Vasilieva
Ravil A
RA
Khatypov
Anatoly Ya
AY
Shkuropatov
Vladimir A
VA
Shuvalov
D019943:Amino Acid Substitution; D001429:Bacteriochlorophylls / Q000378:metabolism*; D004579:Electron Transport; D004591:Electrophoresis, Polyacrylamide Gel; D006639:Histidine / Q000235:genetics*; D007532:Isoleucine / Q000235:genetics*; D008958:Models, Molecular; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D010860:Pigments, Biological / Q000378:metabolism; D011485:Protein Binding; D021122:Protein Subunits / Q000378:metabolism*; D012242:Rhodobacter sphaeroides / Q000378:metabolism*; D013053:Spectrophotometry; D013696:Temperature
D001429:Bacteriochlorophylls; D045322:Photosynthetic Reaction Center Complex Proteins; D010860:Pigments, Biological; D021122:Protein Subunits; D007532:Isoleucine; D006639:Histidine