Coiled-Coil Structure of Group A Streptococcal M Proteins. Different Temperature Stability of Class A and C Proteins by Hydrophobic−Nonhydrophobic Amino Acid Substitutions at Heptad Positions a and d†

Biochemistry ◽  
1997 ◽  
Vol 36 (16) ◽  
pp. 4987-4994 ◽  
Author(s):  
Tommy Cedervall ◽  
Maria U. Johansson ◽  
Bo Åkerström
Keyword(s):  
Amino Acid ◽  
Coiled Coil ◽  
Temperature Stability ◽  
Amino Acid Substitutions ◽  
Class A ◽  
Coil Structure ◽  
M Proteins ◽  
Group A ◽  
C Proteins

scholarly journals Antigenic domains of the streptococcal Pep M5 protein. Localization of epitopes crossreactive with type 6 M protein and identification of a hypervariable region of the M molecule.

1986 ◽  
Vol 163 (1) ◽  
pp. 129-138 ◽  
Author(s):  
B N Manjula ◽  
A S Acharya ◽  
T Fairwell ◽  
V A Fischetti
Keyword(s):  
Protein Localization ◽  
Hypervariable Region ◽  
Coiled Coil ◽  
M Protein ◽  
Terminal Domain ◽  
Coil Structure ◽  
M Proteins ◽  
Group A ◽  
Antigenic Domains ◽  
Antigenic Epitopes

Pep M5, the pepsin-derived N-terminal half of the group A streptococcal type 5 M protein exhibits immunologic crossreaction with type 6 M protein, localizing some of the M6-crossreactive epitope(s) within this segment of the M5 protein. Based on the amino acid sequence of the Pep M5 protein, two structurally distinct domains have been recognized within its coiled-coil structure. We have now found that peptides derived from both the structurally distinct domains of the Pep M5 protein contain antigenic epitopes. Furthermore, only the peptides from the C-terminal domain of the Pep M5 protein crossreacted with rabbit anti-M6 sera, whereas those from the N-terminal domain did not. Consistent with this, sequence analyses of the arginyl peptides of the Pep M6 protein, the pepsin-derived N-terminal half of the M6 protein, revealed extensive homology of some of these peptides with regions within the C-terminal domain of the Pep M5 molecule. While an arginyl peptide of the Pep M6 protein exhibits 84% homology with region 150-186 of the Pep M5 protein, the C-terminal hexadecapeptide of the Pep M6 protein is virtually identical with the corresponding region of the Pep M5 protein. These results are suggestive of conformational similarities in the region around the pepsin-susceptible site within the M5 and M6 proteins. In addition, one or more epitopes of the M5 protein that are crossreactive with the M6 protein may be placed close to the pepsin-susceptible site of the M5 protein. Previous studies have suggested the N-terminal half of the M proteins to be the variable part of the molecule among the different M protein serotypes. The present results suggest that the N-terminal quarter of the M protein may represent the hypervariable domain of the M molecule.

scholarly journals Amino acid substitutions in human growth hormone affect coiled-coil content and receptor binding

2021 ◽  
Author(s):  
Andrei Rajkovic ◽  
Sandesh Kanchugal ◽  
Eldar Abdurakhmanov ◽  
Rebecca Howard ◽  
Astrid Gräslund ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Amino Acid ◽  
Binding Site ◽  
Human Growth Hormone ◽  
Receptor Binding ◽  
Coiled Coil ◽  
Human Growth ◽  
Zinc Binding ◽  
Amino Acid Substitutions ◽  
Great Relevance

The interaction between human Growth Hormone (hGH) and hGH Receptor (hGHR) has great relevance to human diseases such as acromegaly and cancer. HGH has been extensively engineered by other workers to improve binding and other properties. We used a computational screen to select substitutions at single hGH positions within the hGHR-binding site. We find that, while many successfully slow down dissociation of the hGH-hGHR complex once bound, they also slow down the association of hGH to hGHR. We are particularly interested in E174 which belongs to the hGH zinc-binding triad, and which spans coiled-coil helices and obeys the coiled-coil heptad pattern. Surprisingly, substituting E174 with A leads to substantial increase in an experimental measure of coiled-coil content. E174A is known to increase affinity of hGH against hGHR; here we show that this is simply because the off-rate is slowed down more than the on-rate, in line with what has been found for other affinity-improving mutations. For E174Y (and mutations at other sites) the slowdown in on-rate was greater, leading to decreased affinity. The results point to a link between coiled-coiling, zinc binding, and hGHR-binding affinity in hGH, and also suggest rules for choosing affinity-increasing substitutions.

Cysteine Sequences of Rabbit Skeletal Tropomyosin

1972 ◽  
Vol 50 (3) ◽  
pp. 330-343 ◽  
Author(s):  
R. S. Hodges ◽  
L. B. Smillie
Keyword(s):  
Amino Acid ◽  
Acid Hydrolysis ◽  
Coiled Coil ◽  
Iodoacetic Acid ◽  
Amino Acid Sequences ◽  
Cysteic Acid ◽  
Chain Packing ◽  
Hydrophobic Residues ◽  
Coil Structure ◽  
Cysteine Content

Amino acid analyses of tropomyosin have shown three cysteine residues per mole (M.W. 70 000) of tropomyosin. The cysteine content was determined by cysteic acid determinations, incorporation of 14C-labelled iodoacetic acid into the protein, and the analysis of S-carboxymethylcysteine after acid hydrolysis. The isolation of three unique cysteinyl peptides is incompatible with a homogeneous tropomyosin preparation of two chemically identical subunits. The amino acid sequences reported in this study indicate a regular repeat of hydrophobic residues as required by the inter-chain packing of a coiled-coil structure.

Effects of side-chain characteristics on stability and oligomerization state of a de Novo -designed model coiled-coil: 20 amino acid substitutions in position “d” 1 1Edited by P. E. Wright

2000 ◽  
Vol 300 (2) ◽  
pp. 377-402 ◽  
Author(s):  
Brian Tripet ◽  
Kurt Wagschal ◽  
Pierre Lavigne ◽  
Colin T. Mant ◽  
Robert S. Hodges
Keyword(s):  
Amino Acid ◽  
De Novo ◽  
Coiled Coil ◽  
Side Chain ◽  
Amino Acid Substitutions

scholarly journals Amino acid sequences of α-helical segments from S-carboxymethylkerateine-A. Complete sequence of a type-II segment

1978 ◽  
Vol 173 (2) ◽  
pp. 365-371 ◽  
Author(s):  
W G Crewther ◽  
A S Inglis ◽  
N M McKern
Keyword(s):  
Amino Acid ◽  
Coiled Coil ◽  
Complete Sequence ◽  
Amino Acid Sequences ◽  
Helical Axis ◽  
Type I ◽  
Type Ii ◽  
Coil Structure ◽  
Aqueous Urea ◽  
Alpha Keratin

1. The helical fragments obtained by partial chymotryptic digestion of S-carboxymethylkeratine-A, the low-sulphur fraction from wool, were fractionated into type-I and type-II helical segments in aqueous urea under conditions limiting carbamoylation. 2. The amino acid sequence of a 109-residue type-II segment was completed by using the sequenator. 3. When the data were incorporated into a helical model of 3.6 residues per turn the hydrophobic residues generated a band aligned at a slight angle to the helical axis. This result is in accord with the postulated coiled-coil structure of the crystalline regions of alpha-keratin.

Isolation of Group A Streptococci with Reduced In Vitro β-Lactam Susceptibility Harboring Amino Acid Substitutions in Penicillin-Binding Proteins in Japan

2021 ◽  
Author(s):  
Tsubasa Ikeda ◽  
Rihito Suzuki ◽  
Wanchun Jin ◽  
Jun-ichi Wachino ◽  
Yoshichika Arakawa ◽  
...  
Keyword(s):  
United States ◽  
Amino Acid ◽  
Streptococcus Pyogenes ◽  
The United States ◽  
Amino Acid Substitutions ◽  
Group A Streptococci ◽  
Penicillin Binding Protein ◽  
Penicillin Binding Proteins ◽  
Group A

Streptococcus pyogenes (group A Streptococcus , GAS) has long been regarded as being susceptible to β-lactams. However, amino acid substitutions in penicillin-binding protein (PBP)2X conferring reduced in vitro β-lactam susceptibility have been indicated since 2019 in the United States and Iceland. Here, we report the first isolation of Streptococcus pyogenes possessing the PBP2X substitution conferring reduced in vitro β-lactam susceptibility in Asia; however, the MICs were below the “susceptible” breakpoint of the CLSI.

The Histidine and Methionine Sequences of Rabbit Skeletal Tropomyosin

1972 ◽  
Vol 50 (3) ◽  
pp. 312-329 ◽  
Author(s):  
R. S. Hodges ◽  
L. B. Smillie
Keyword(s):  
Amino Acid ◽  
Sequence Analysis ◽  
Amino Acid Sequence ◽  
Coiled Coil ◽  
Sequence Information ◽  
Chain Packing ◽  
Hydrophobic Residues ◽  
Coil Structure ◽  
Methionine Residues ◽  
Polypeptide Chains

Amino acid analyses of tropomyosin have previously shown four histidine and 13–14 methionine residues per mole (70 000 daltons) of tropomyosin. The isolation of two unique histidyl and five unique methionyl sequences is described. The number of unique methionyl peptides will undoubtedly be increased when more extensive sequence information becomes available although the value of 2 for the unique histidine sequences is considered to be a maximal one. These data support the conclusion that the two subunits of tropomyosin are similar in amino acid sequence. Both the acetylated NH2-terminal and COOH-terminal sequences of the protein have been determined in this study. The isolation and sequence analysis of two varieties of peptides arising from the COOH-terminus of the protein indicates either a degree of proteolysis during its isolation or a difference in the constituent polypeptide chains of tropomyosin in this region of their structures. The limited sequences reported indicate a repeat of hydrophobic residues as required by the inter-chain packing of a coiled-coil structure.

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