Chemical Modification of the Rieske Protein fromThermus thermophilusUsing Diethyl Pyrocarbonate Modifies Ligating Histidine 154 and Reduces the [2Fe-2S] Cluster

Biochemistry ◽  
2010 ◽  
Vol 49 (34) ◽  
pp. 7272-7281 ◽  
Author(s):  
Mary E. Konkle ◽  
Kaitlin N. Elsenheimer ◽  
Kevin Hakala ◽  
Jennifer C. Robicheaux ◽  
Susan T. Weintraub ◽  
...  
Keyword(s):  
Chemical Modification ◽  
Rieske Protein ◽  
Diethyl Pyrocarbonate

Stabilization of Tumor Antigens by Chemical Modification with Diethyl Pyrocarbonate

1990 ◽  
Vol 54 (7) ◽  
pp. 1615-1622
Author(s):  
Youichi Tamai ◽  
Lahu Yang ◽  
Hiroshi Shinmoto ◽  
Yasuo Watanabe
Keyword(s):  
Chemical Modification ◽  
Tumor Antigens ◽  
Diethyl Pyrocarbonate

Chemical modification ofSemele solida arginase by diethyl pyrocarbonate: Evidence for a critical histidine residue

1996 ◽  
Vol 114 (4) ◽  
pp. 367-370 ◽  
Author(s):  
Nelson Carvajal ◽  
Elena Uribe ◽  
Marcela Sepu´lveda ◽  
Cristian Mendoza ◽  
Bernardo Fuentealba ◽  
...  
Keyword(s):  
Chemical Modification ◽  
Histidine Residue ◽  
Diethyl Pyrocarbonate

scholarly journals Interaction between complement subcomponent C1q and bacterial lipopolysaccharides

1989 ◽  
Vol 257 (3) ◽  
pp. 865-873 ◽  
Author(s):  
A Zohair ◽  
S Chesne ◽  
R H Wade ◽  
M G Colomb
Keyword(s):  
Escherichia Coli ◽  
Chemical Modification ◽  
Essential Role ◽  
Wild Strain ◽  
E Coli ◽  
Diethyl Pyrocarbonate ◽  
Direct Binding ◽  
Bacterial Lipopolysaccharides ◽  
K 12

The heptose-less mutant of Escherichia coli, D31m4, bound complement subcomponent C1q and its collagen-like fragments (C1qCLF) with Ka values of 1.4 x 10(8) and 2.0 x 10(8) M-1 respectively. This binding was suppressed by chemical modification of C1q and C1qCLF using diethyl pyrocarbonate (DEPC). To investigate the role of lipopolysaccharides (LPS) in this binding, biosynthetically labelled [14C]LPS were purified from E. coli D31m4 and incorporated into liposomes prepared from phosphatidylcholine (PC) and phosphatidylethanolamine (PE) [PC/PE/LPS, 2:2:1, by wt.]. Binding of C1q or its collagen-like fragments to the liposomes was estimated via a flotation test. These liposomes bound C1q and C1qCLF with Ka values of 8.0 x 10(7) and 2.0 x 10(7) M-1; this binding was totally inhibited after chemical modification of C1q and C1qCLF by DEPC. Liposomes containing LPS purified from the wild-strain E. coli K-12 S also bound C1q and C1qCLF, whereas direct binding of C1q or C1qCLF to the bacteria was negligible. Diamines at concentrations which dissociate C1 into C1q and (C1r, C1s)2, strongly inhibited the interaction of C1q or C1qCLF with LPS. Removal of 3-deoxy-D-manno-octulosonic acid (2-keto-3-deoxyoctonic acid; KDO) from E. coli D31m4 LPS decreases the binding of C1qCLF to the bacteria by 65%. When this purified and modified LPS was incorporated into liposomes, the C1qCLF binding was completely abolished. These results show: (i) the essential role of the collagen-like moiety and probably its histidine residues in the interaction between C1q and the mutant D31m4; (ii) the contribution of LPS, particularly the anionic charges of KDO, to this interaction.

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