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Category: Microbial Genetics and Molecular Biology
Structural and Functional Conservation in Response Regulators, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555818319/9781555810894_Chap04-1.gif /docserver/preview/fulltext/10.1128/9781555818319/9781555810894_Chap04-2.gifAbstract:
Most response regulators are multidomain proteins. This chapter focuses on the details of these structures, with the intent of deriving structure and function principles applicable to the regulatory domains of all two-component systems. The first indication of a family of bacterial response regulators appeared in 1985, when the amino acid sequence of CheY was shown to be related to regulatory proteins of other cellular processes, such as membrane protein synthesis and sporulation. A comprehensive structure-function analysis of 103 amino acid sequences of response regulators appeared in late 1993. The CheY family includes the short single-domain response regulators, whereas all others are multi-domain proteins. The five standard domain types of multi-domain response regulators are found in various combinations, joined together by flexible linkers. The chapter presents a narrative guide through the CheY molecule, highlighting the interactions that serve as its principal structural determinants. Mg2+ is required for the phosphoryl group transfer reactions of CheY and, presumably, all other response regulators. Phosphorylation is the required primary event in the activation of CheY and, presumably, all normally functioning response regulators, but phosphorylation and activation can be unlinked.
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Stereo diagram of overall structure of CheY. See discussion in text.
Stereo diagram of overall structure of CheY. See discussion in text.
(A) Amino acid preference plot for regulatory domains of the response regulator superfamily. A histogram of the percent occurrence of each amino acid type is plotted against CheY numbering. Each bar represents the occurrence of each amino acid type divided by the total number of amino acids per site in the multiple alignment of 79 sequences from Volz ( Volz, 1993 ). Gaps are not counted. Values less than 10% are omitted for clarity, so the sums for most positions do not reach 100%. The color code is acidic (D, E), red; hydroxyl (S, T), rose; hydrophobic (C, I, L,M, V),yellow; aromatic (F,W,Y),green;polar (H,N,Q),light blue; basic (K,R), dark blue; and structural (A, G, P), light gray. The secondary structural elements of the CheY molecule are shown at the top. (B) Stereo diagram of three-dimensional distribution of amino acid preferences on overall structure of CheY. Amino acid residue types are color coded as in A. The orientation is approximately the same as in Fig. 1 . Highly conserved positions are labeled. The side chains of D12, D13,D57,T87,andK109 are also shown.
(A) Amino acid preference plot for regulatory domains of the response regulator superfamily. A histogram of the percent occurrence of each amino acid type is plotted against CheY numbering. Each bar represents the occurrence of each amino acid type divided by the total number of amino acids per site in the multiple alignment of 79 sequences from Volz ( Volz, 1993 ). Gaps are not counted. Values less than 10% are omitted for clarity, so the sums for most positions do not reach 100%. The color code is acidic (D, E), red; hydroxyl (S, T), rose; hydrophobic (C, I, L,M, V),yellow; aromatic (F,W,Y),green;polar (H,N,Q),light blue; basic (K,R), dark blue; and structural (A, G, P), light gray. The secondary structural elements of the CheY molecule are shown at the top. (B) Stereo diagram of three-dimensional distribution of amino acid preferences on overall structure of CheY. Amino acid residue types are color coded as in A. The orientation is approximately the same as in Fig. 1 . Highly conserved positions are labeled. The side chains of D12, D13,D57,T87,andK109 are also shown.
Stereo diagram of CheY region containing the most highly conserved residues of the superfamily. The orientation is approximately the same as in Figs. 1 and 2B . See discussion in text.
Stereo diagram of CheY region containing the most highly conserved residues of the superfamily. The orientation is approximately the same as in Figs. 1 and 2B . See discussion in text.
Stereo diagram of superposition of apo-CheY and the two CheY:Mg2+ complex structures. Details of active sites. The color code is white, wild-type E. coli apo-CheY; red, wild-type E. coli CheY:Mg2+; blue, wild-type S. typhimurium CheY:Mg2+. From the coordinates of Volz and Matsumura (1991) ; Bellsolell et al. (1994) ; and Stock et al. (1993) . The orientation is rotated about 40° in the plane of the page as compared with Figs. 1 , 2B , and 3 . See discussion in text.
Stereo diagram of superposition of apo-CheY and the two CheY:Mg2+ complex structures. Details of active sites. The color code is white, wild-type E. coli apo-CheY; red, wild-type E. coli CheY:Mg2+; blue, wild-type S. typhimurium CheY:Mg2+. From the coordinates of Volz and Matsumura (1991) ; Bellsolell et al. (1994) ; and Stock et al. (1993) . The orientation is rotated about 40° in the plane of the page as compared with Figs. 1 , 2B , and 3 . See discussion in text.
Structural roles o f “conserved” residues in CheY
Structural roles o f “conserved” residues in CheY