scholarly journals Amino acid sequence and length requirements for assembly and function of the colicin A lysis protein.

1989 ◽  
Vol 171 (1) ◽  
pp. 410-418 ◽  
Author(s):  
S P Howard ◽  
D Cavard ◽  
C Lazdunski
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
And Function

Chitosanase from Streptomyces sp. strain N174: a comparative review of its structure and function

1997 ◽  
Vol 75 (6) ◽  
pp. 687-696 ◽  
Author(s):  
Tamo Fukamizo ◽  
Ryszard Brzezinski
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Substrate Binding ◽  
Structure And Function ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Amino Acid Residues ◽  
Streptomyces Sp ◽  
Binding Cleft ◽  
And Function

Novel information on the structure and function of chitosanase, which hydrolyzes the beta -1,4-glycosidic linkage of chitosan, has accumulated in recent years. The cloning of the chitosanase gene from Streptomyces sp. strain N174 and the establishment of an efficient expression system using Streptomyces lividans TK24 have contributed to these advances. Amino acid sequence comparisons of the chitosanases that have been sequenced to date revealed a significant homology in the N-terminal module. From energy minimization based on the X-ray crystal structure of Streptomyces sp. strain N174 chitosanase, the substrate binding cleft of this enzyme was estimated to be composed of six monosaccharide binding subsites. The hydrolytic reaction takes place at the center of the binding cleft with an inverting mechanism. Site-directed mutagenesis of the carboxylic amino acid residues that are conserved revealed that Glu-22 and Asp-40 are the catalytic residues. The tryptophan residues in the chitosanase do not participate directly in the substrate binding but stabilize the protein structure by interacting with hydrophobic and carboxylic side chains of the other amino acid residues. Structural and functional similarities were found between chitosanase, barley chitinase, bacteriophage T4 lysozyme, and goose egg white lysozyme, even though these proteins share no sequence similarities. This information can be helpful for the design of new chitinolytic enzymes that can be applied to carbohydrate engineering, biological control of phytopathogens, and other fields including chitinous polysaccharide degradation. Key words: chitosanase, amino acid sequence, overexpression system, reaction mechanism, site-directed mutagenesis.

scholarly journals High-grade mutant OmpF induces decreased bacterial survival rate.

2014 ◽  
Vol 61 (2) ◽  
Author(s):  
Zhi-ping Zhao ◽  
Ting-ting Liu ◽  
Li Zhang ◽  
Min Luo ◽  
Xin Nie ◽  
...  
Keyword(s):  
Amino Acid ◽  
Survival Rate ◽  
Sequence Analysis ◽  
Amino Acid Sequence ◽  
Inhibition Zone ◽  
Structure And Function ◽  
High Grade ◽  
Bacterial Survival ◽  
Antibiotic Inhibition ◽  
And Function

OmpF plays very important roles in the influx of antibiotics and bacterial survival in the presence of antibiotics. However, high-grade mutant OmpF and its function in decreasing bacterial survival rate have not been reported to date. In the present study, we cloned a high-grade mutant OmpF (mOmpF) and sequence analysis suggested that over 45 percent of the DNA sequence was significantly mutated, leading to dramatic changes in over 55 percent of the amino acid sequence. mOmpF protein was successfully expressed. When grown in the presence of antibiotic, the bacterial survival rate decreased and the antibiotic inhibition zone became larger with the increase of the mOmpF. It was concluded that concentration of high-grade mutant mOmpF dramatically influenced the bacterial survival rate. The study presented here may provide insights into better understanding of the relationships between structure and function of OmpF.

scholarly journals Interaction between FliE and FlgB, a Proximal Rod Component of the Flagellar Basal Body ofSalmonella

2000 ◽  
Vol 182 (11) ◽  
pp. 3029-3036 ◽  
Author(s):  
Tohru Minamino ◽  
Shigeru Yamaguchi ◽  
Robert M. Macnab
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Basal Body ◽  
Strong Interactions ◽  
Wild Type ◽  
Body Protein ◽  
C Terminus ◽  
Genes Encoding ◽  
And Function ◽  
Better Than

ABSTRACT FliE is a flagellar basal body protein of Salmonellawhose detailed location and function have not been established. A mutant allele of fliE, which caused extremely poor flagellation and swarming, generated extragenic suppressors, all of which mapped to flgB, one of four genes encoding the basal body rod; the fliE flgB pseudorevertants were better flagellated and swarmed better than the fliE parent, especially when the temperature was reduced from 37 to 30°C. Motility of the pseudorevertants in liquid culture was markedly better than motility on swarm plates; we interpret this to mean that reduced flagellation is less deleterious at low viscous loads. Overproduction of the mutant FliE protein improved the motility of the parentalfliE mutant and its pseudorevertants, though not to wild-type levels. Overproduction of suppressor FlgB (but not wild-type FlgB) in the fliE mutant also resulted in improved motility. The second-site FlgB mutation by itself had no phenotype; cells swarmed as well as wild-type cells. When overproduced, wild-type FliE was dominant over FliE-V99G, but the reverse was not true; that is, overproduced FliE-V99G was not negatively dominant over wild-type FliE. We conclude that the mutant protein has reduced probability of assembly but, if assembled, functions relatively well. Export of the flagellar protein FlgD, which is known to be FliE dependent, was severely impaired by the FliE-V99G mutation but was significantly improved in the suppressor strains. The FliE mutation, V99G, was close to the C terminus of the 104-amino-acid sequence; the suppressing mutations in FlgB were all either G119E or G129D, close to the C terminus of its 138-amino-acid sequence. Affinity blotting experiments between FliE as probe and various basal body proteins as targets and vice versa revealed strong interactions between FliE and FlgB; much weaker interactions between FliE and other rod proteins were observed and probably derive from the known similarities among these proteins. We suggest that FliE subunits constitute a junction zone between the MS ring and the rod and also that the proximal rod structure consists of FlgB subunits.

scholarly journals Primary Structure of Apovitellenin I From Hen Egg Yolk and its Comparison With Emu Apovitellenin I

1976 ◽  
Vol 29 (3) ◽  
pp. 175 ◽  
Author(s):  
TAA Dopheide ◽  
AS Inglis
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Primary Structure ◽  
Egg Yolk ◽  
Structure And Function ◽  
Single Base ◽  
Hen Egg Yolk ◽  
Considerable Homology ◽  
And Function ◽  
Hen Egg

The amino acid sequence of apovitellenin I from hen egg yolk has been determined using both automatic and manual procedures; it comprises 82 residues. Hen apovitellenin shows considerable homology with emu apovitellenin I which contains 84 residues. Besides two deletions in the sequence, the hen protein differs in 28 positions from the emu protein; 26 of these positions may have arisen from single base changes. The changes are largely conservative ones, which suggest that the structure and function have been preserved despite extensive mutation.

scholarly journals Amino acid sequence conservation of the algesic fragment of myelin basic protein is required for its interaction with CDK 5 and function in pain

FEBS Journal ◽  
2018 ◽  
Vol 285 (18) ◽  
pp. 3485-3502
Author(s):  
Andrei V. Chernov ◽  
Albert G. Remacle ◽  
Swathi K. Hullugundi ◽  
Piotr Cieplak ◽  
Mila Angert ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Myelin Basic Protein ◽  
Basic Protein ◽  
Sequence Conservation ◽  
And Function ◽  
Amino Acid Sequence Conservation

scholarly journals DRS1 to DRS7, novel genes required for ribosome assembly and function in Saccharomyces cerevisiae.

1993 ◽  
Vol 13 (12) ◽  
pp. 7901-7912 ◽  
Author(s):  
T L Ripmaster ◽  
G P Vaughn ◽  
J L Woolford
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Elongation Factor ◽  
Ribosome Assembly ◽  
Predicted Amino Acid Sequence ◽  
Phosphate Binding ◽  
Ribosomal Subunits ◽  
Cold Sensitive ◽  
And Function

To identify Saccharomyces cerevisiae mutants defective in assembly or function of ribosomes, a collection of cold-sensitive strains generated by treatment with ethyl methanesulfonate was screened by sucrose gradient analysis for altered ratios of free 40S to 60S ribosomal subunits or qualitative changes in polyribosome profiles. Mutations defining seven complementation groups deficient in ribosomal subunits, drs1 to drs7, were identified. We have previously shown that DRS1 encodes a putative ATP-dependent RNA helicase necessary for assembly of 60S ribosomal subunits (T. L. Ripmaster, G. P. Vaughn, and J. L. Woolford, Jr., Proc. Natl. Acad. Sci. USA 89:11131-11135, 1992). Strains bearing the drs2 mutation process the 20S precursor of the mature 18S rRNA slowly and are deficient in 40S ribosomal subunits. Cloning and sequencing of the DRS2 gene revealed that it encodes a protein similar to membrane-spanning Ca2+ ATPases. The predicted amino acid sequence encoded by DRS2 contains seven transmembrane domains, a phosphate-binding loop found in ATP- or GTP-binding proteins, and a seven-amino-acid sequence detected in all classes of P-type ATPases. The cold-sensitive phenotype of drs2 is suppressed by extra copies of the TEF3 gene, which encodes a yeast homolog of eukaryotic translation elongation factor EF-1 gamma. Identification of gene products affecting ribosome assembly and function among the DNAs complementing the drs mutations validates the feasibility of this approach.

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