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.
Fufina
Tatiana Y
TY
Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russia.
Vasilieva
Lyudmila G
LG
Khatypov
Ravil A
RA
Shkuropatov
Anatoly Ya
AY
Shuvalov
Vladimir A
VA
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