Proteins with Spectrin Motifs Which Do Not Belong to the Spectrin-α-Actinin- Dystrophin Family

2004 ◽  
Vol 59 (7-8) ◽  
pp. 565-571 ◽  
Author(s):  
Maciej Kukuła ◽  
Beata Hanus-Lorenz ◽  
Ewa Bok ◽  
Jacek Leluk ◽  
Aleksander F. Sikorski
Keyword(s):  
Amino Acid ◽  
Early Stage ◽  
Variable Number ◽  
Amino Acid Residues ◽  
Significant Similarity ◽  
Spectrin Repeat ◽  
Consensus Sequences ◽  
Homology Relationship ◽  
Relationship Of ◽  
High Degree

AbstractUsing several consensus sequences for the 106 amino acid residue α-spectrin repeat segment as probes we searched animal sequence databases using the BLAST program in order to find proteins revealing limited, but significant similarity to spectrin. Among many spectrins and proteins from the spectrin-α-actinin-dystrophin family as well as sequences showing a rather high degree of similarity in very short stretches, we found seven homologous animal sequences of low overall similarity to spectrin but showing the presence of one or more spectrin-repeat motifs. The homology relationship of these sequences to α-spectrin was further analysed using the SEMIHOM program. Depending on the probe, these segments showed the presence of 6 to 26 identical amino acid residues and a variable number of semihomologous residues. Moreover, we found six protein sequences, which contained a sequence fragment sharing the SH3 (sarc homology region 3) domain homology of 42-59% similarity. Our data indicate the occurrence of motifs of significant homology to α-spectrin repeat segments among animal proteins, which are not classical members of the spectrin-α- actinin-dystrophin family. This might indicate that these segments together with the SH3 domain motif are conserved in proteins which possibly at the early stage of evolution were close cognates of spectrin-α-actinin-dystrophin progenitors but then evolved separately.

scholarly journals Localization of regions of a Bordetella pertussis autotransporter, Vag8, interacting with C1 inhibitor

2020 ◽  
Author(s):  
Naoki Onoda ◽  
Yukihiro Hiramatsu ◽  
Shihono Teruya ◽  
Koichiro Suzuki ◽  
Yasuhiko Horiguchi
Keyword(s):  
Amino Acid ◽  
Bordetella Pertussis ◽  
Serine Proteases ◽  
Whooping Cough ◽  
Amino Acid Residues ◽  
C1 Inhibitor ◽  
Passenger Domain ◽  
Complement Regulator ◽  
Function Relationship ◽  
Relationship Of

AbstractBordetella pertussis is the causative agent of pertussis (whooping cough), a contagious respiratory disease that has recently seen a resurgence despite high vaccination coverage, necessitating improvement of current pertussis vaccines. An autotransporter of B. pertussis, virulence-associated gene 8 (Vag8), has been proposed as an additional component to improve pertussis vaccines. Vag8 is known to play a role in evasion of the complement system and activation of the contact system by inactivating the complement regulating factor, C1 inhibitor (C1 Inh), which inhibits serine proteases, such as plasma kallikrein (PK). However, the nature of the molecular interaction between Vag8 and C1 Inh remains to be determined. In the present study, we attempted to determine the minimum region of Vag8 that interacts with C1 Inh by examining the differently–truncated Vag8 derivatives for the ability to bind and inactivate C1 Inh. The region of Vag8 from amino–acid residues 102 to 548 was found to bind C1 Inh and cancel its inhibitory action on the protease activity of PK at the same level as a Vag8 fragment from amino–acid residues 52 to 648 covering the passenger domain, which carries its extracellular function. In contrast, the truncated Vag8 containing amino–acid residues 102 – 479 or 202 – 648 barely interacted with C1 Inh. These results indicated that the two separate regions of amino–acid residues 102 – 202 and 479 – 548 are likely required for the interaction with C1 Inh.ImportancePertussis is currently reemerging worldwide, and is still one of the greatest disease burdens in infants. B. pertussis produces a number of virulence factors, including toxins, adhesins, and autotransporters. One of the autotransporters, Vag8, which binds and inactivates the complement regulator C1 Inh, is considered to contribute to the establishment of B. pertussis infection. However, the nature of the interaction between Vag8 and C1 Inh remains to be explored. In this study, we narrowed down the region of Vag8 that interacts with C1 Inh and demonstrated that at least two separate regions of Vag8 are necessary for the interaction with C1 Inh. Our results provide insight into the structure–function relationship of the Vag8 molecule and information to determine its potential role in the pathogenesis of B. pertussis.

scholarly journals The Differential Binding Affinities of the Luteinizing Hormone (LH)/Choriogonadotropin Receptor for LH and Choriogonadotropin Are Dictated by Different Extracellular Domain Residues

2005 ◽  
Vol 19 (5) ◽  
pp. 1263-1276 ◽  
Author(s):  
Colette Galet ◽  
Mario Ascoli
Keyword(s):  
Amino Acid ◽  
Ligand Binding ◽  
Binding Affinity ◽  
Extracellular Domain ◽  
Binding Affinities ◽  
Amino Acid Residues ◽  
Identify Amino Acid ◽  
Β Sheets ◽  
Leucine Rich Repeats ◽  
High Degree

Abstract The high degree of amino acid sequence homology and the divergent ligand binding affinities of the rat (r) and human (h) LH receptors (LHRs) allowed us to identify amino acid residues of their extracellular domain that are responsible for the different binding affinities of bovine (b) and hLH, and human choriogonadotropin (hCG) to the hLHR and rLHR. Because of the proposed importance of the β-sheets of the leucine-rich repeats (LRRs) of the extracellular domain of the LHR on hormone binding, we examined 10 divergent residues present in these regions by analyzing two complementary sets of mutants in which hLHR residues were substituted with the corresponding rLHR residues and vice versa. These experiments resulted in the identification of a single residue (a Ile or Ser in the C-terminal end of LRR2 of the hLHR or rLHR, respectively) that is important for hLH binding affinity. Surprisingly, however, this residue does not affect hCG or for bLH binding affinity. In fact, the results obtained with bLH and hCG show that several of the divergent residues in the β-sheets of LRR1–9 affect bLH binding affinity, but none of them affect hCG binding affinity. Importantly, our results also emphasize the involvement of residues outside of the β-sheets of the LRRs of the LHR in ligand binding affinity. This finding has to be considered in future models of the interaction of LH/CG with the LHR.

scholarly journals The ς70 Transcription Factor TyrR Has Zinc-Stimulated Phosphatase Activity That Is Inhibited by ATP and Tyrosine

2000 ◽  
Vol 182 (4) ◽  
pp. 1053-1061 ◽  
Author(s):  
Shimin Zhao ◽  
Qin Zhu ◽  
Ronald L. Somerville
Keyword(s):  
Amino Acid ◽  
Phosphatase Activity ◽  
Sequence Similarity ◽  
Zinc Ion ◽  
Amino Acid Residues ◽  
Protein Residues ◽  
E Coli ◽  
C Terminus ◽  
Atp Analogues ◽  
High Degree

ABSTRACT The TyrR protein of Escherichia coli (513 amino acid residues) is the chief transcriptional regulator of a group of genes that are essential for aromatic amino acid biosynthesis and transport. The TyrR protein can function either as a repressor or as an activator. The central region of the TyrR protein (residues 207 to 425) is similar to corresponding polypeptide segments of the NtrC protein superfamily. Like the NtrC protein, TyrR has intrinsic ATPase activity. Here, we report that TyrR possesses phosphatase activity. This activity is subject to inhibition by l-tyrosine and its analogues and by ATP and ATP analogues. Zinc ion (2 mM) stimulated the phosphatase activity of the TyrR protein by a factor of 57. The phosphatase-active site of TyrR was localized to a 31-kDa domain (residues 191 to 467) of the protein. However, mutational alteration of distant amino acid residues at both the N terminus and the C terminus of TyrR altered the phosphatase activity. Haemophilus influenzae TyrR (318 amino acid residues), a protein with a high degree of sequence similarity to the C terminus of the E. coli TyrR protein, exhibited a phosphatase activity similar to that of E. coliTyrR.

scholarly journals Structural studies on wheat (Triticum aestivum) proteins lacking phenylalanine and histidine residues

1975 ◽  
Vol 149 (3) ◽  
pp. 725-732 ◽  
Author(s):  
D G Redman
Keyword(s):  
Amino Acids ◽  
Triticum Aestivum ◽  
Amino Acid ◽  
Structural Studies ◽  
Amino Acid Residues ◽  
Sequencing Studies ◽  
Arginine Residues ◽  
Terminal Amino ◽  
Methionine Residues ◽  
High Degree

1. Three very similar proteins, each of approx. 120 amino acid residues but lacking phenylalanine and histidine, were isolated from wheat (Triticum aestivum) flour in sufficient quantities for further structural studies. 2. Each protein, after reduction and carboxymethylation, was cleaved at the three methionine residues with CNBr to give four major peptides, which were isolated. These peptides are suitable for future sequencing studies, as the sums of their amino acid compositions are in good agreement with those of the whole proteins. 3. The N- and C-terminal peptides were identified. 4. Evidence from amino acid analyses, N-terminal amino acids and electrophoretic mobilities of the peptides suggests a high degree of homology between the proteins. Definite differences in C-terminal amino acids and the number of glycine, alanine and arginine residues were found in the C-terminal peptides.

Molecular cloning and hormonal control in the ovary of connexin 31.5 mRNA and correlation with the appearance of oocyte maturational competence in red seabream

2000 ◽  
Vol 203 (21) ◽  
pp. 3299-3306
Author(s):  
C.Y. Choi ◽  
F. Takashima
Keyword(s):  
Amino Acid ◽  
Hormonal Control ◽  
Predicted Amino Acid Sequence ◽  
Amino Acid Residues ◽  
Reading Frame ◽  
Red Seabream ◽  
Consensus Sequences ◽  
Cdna Sequences ◽  
Connexin Gene ◽  
Connexin Genes

Gap junctions are aggregates of intercellular channels, composed of the protein connexin (Cx), between adjacent cells. This study examined whether, in the ovary of the red seabream Pagrus major, the connexin gene essential for the production of RNA and protein during the acquisition of oocyte maturational competence is active. Mixed primers for this reaction were designed on the basis of the high sequence homology of selected regions of known connexin genes. Polymerase-chain-reaction-amplified cDNA fragments generated by 3′ and 5′ rapid amplication of cDNA ends were combined to generate full-length cDNA sequences. The resulting 2400 base pair cDNA had an open reading frame encoding a polypeptide containing 275 amino acid residues (31493 Da; Cx31.5). Hydropathicity analysis of the predicted amino acid sequence indicated that red seabream Cx31.5 has four major hydrophobic regions and four major hydrophilic regions indicative of a topology similar to that of known connexins. Typical connexin consensus sequences were also observed in the first and second extracellular loops. During the acquisition of oocyte maturational competence, red seabream Cx31.5 mRNA transcription levels increased after treatment with gonadotropin-II. It is therefore proposed that expression of Cx31.5 contributes to the acquisition of oocyte maturational competence in this species.

scholarly journals Assignment of Amino Acid Residues of the AVR9 Peptide of Cladosporium fulvum That Determine Elicitor Activity

1997 ◽  
Vol 10 (7) ◽  
pp. 821-829 ◽  
Author(s):  
Miriam Kooman-Gersmann ◽  
Ralph Vogelsang ◽  
Erwin C. M. Hoogendijk ◽  
Pierre J. G. M. De Wit
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Resistance Gene ◽  
Expression System ◽  
Potato Virus X ◽  
Cladosporium Fulvum ◽  
Amino Acid Residues ◽  
Tomato Plants ◽  
Loop Region ◽  
Relationship Of

The AVR9 peptide of Cladosporium fulvum is an elicitor of the hypersensitive response in tomato plants carrying the Cf-9 resistance gene (MM-Cf9). To determine the structure-activity relationship of the AVR9 peptide, amino acids important for AVR9 elicitor activity were identified by independently substituting each amino acid of AVR9 by alanine. In addition, surface-exposed amino acid residues of AVR9 were substituted by other amino acids. Activity of the mutant Avr9 constructs was studied by expressing the constructs in MM-Cf9 tomato plants, using the potato virus X (PVX) expression system and assessing the severity of necrosis induced by each PVX∷Avr9 construct. This allowed direct identification of amino acid residues of AVR9 that are essential for elicitor activity. We identified amino acid substitutions that resulted in AVR9 mutants with higher, similar, or lower elicitor activity compared to the wild-type AVR9 peptide. Some mutants had completely lost elicitor activity. A selection of peptides, representing different categories, was isolated and injected into leaves of MM-Cf9 plants. The necrosis-inducing activity of the isolated peptides correlated well with the necrosis induced by the corresponding PVX∷Avr9 derivatives. Based on the necrosis-inducing activity of the mutant AVR9 peptides and the global structure of AVR9, we assigned sites in AVR9 that are important for its necrosis-inducing activity. We postulate that the “hydrophobic β-loop” region of the AVR9 peptide is crucial for necrosis-inducing activity in tomato plants that carry the Cf-9 resistance gene.

Chromogenic substrates as fundamental tool to design new thrombin inhibitors

2005 ◽  
Vol 25 (03) ◽  
pp. 267-271 ◽  
Author(s):  
G. Nowak ◽  
M. Lopez
Keyword(s):  
Amino Acid ◽  
Equilibrium Constant ◽  
Structural Information ◽  
Thrombin Inhibitors ◽  
Thrombin Inhibitor ◽  
Amino Acid Residues ◽  
Chromogenic Assay ◽  
Biological Methods ◽  
Site Blocking ◽  
Relationship Of

SummaryThe structure-activity relationship of dipetalogastin II, the strongest thrombin inhibitor isolated and cloned from the bug Dipetalogaster maximus, was examined by introducing gradual changes into the molecule by means of molecular biological methods. The effect upon its inhibition equilibrium constant was determined after each change by a chromogenic assay. This structural information was fundamental to design new dipetalogastin II-derived inhibitors.Our results suggested that the acidic sequence DEHDHDFEDT corresponding to amino acid residues 49 to 58 of dipetalogastin II reacts with the anion binding exosite (ABE) 1 of thrombin. Based on this finding, we constructed a chimeric molecule consisting of the active site blocking segment of dipetalogastin II (amino acid residues 1 to 48) and the ABE 1 blocking segment of hirudin. This construct showed better thrombin inhibitory activity than both separated segments only after the introduction of a glycine linker between both blocking segments. We thus obtained a thrombin inhibitor called dipetarudin with an inhibition equilibrium constant comparable to that of dipetalogastin II and a molecular mass below that of dipetalogastin.

Molecular and Phylogenetic Analysis of Pyridoxal Phosphate- Dependent Acyltransferase of Exiguobacterium acetylicum

2009 ◽  
Vol 64 (11-12) ◽  
pp. 891-898 ◽  
Author(s):  
Narayanan Rajendran ◽  
Colby Smith ◽  
Williard Mazhawidza
Keyword(s):  
Amino Acid ◽  
Pyridoxal Phosphate ◽  
Extreme Environments ◽  
Pcr Amplification ◽  
Evolutionary Development ◽  
Sequencing Analysis ◽  
Amino Acid Residues ◽  
Exiguobacterium Acetylicum ◽  
Close Relationship ◽  
Relationship Of

The pyridoxal-5’-phosphate (PLP)-dependent family of enzymes is a very diverse group of proteins that metabolize small molecules like amino acids and sugars, and synthesize cofactors for other metabolic pathways through transamination, decarboxylation, racemization, and substitution reactions. In this study we employed degenerated primer-based PCR amplification, using genomic DNA isolated from the soil bacterium Exiguobacterium acetylicum strain SN as template. We revealed the presence of a PLP-dependent family of enzymes, such as PLP-dependent acyltransferase, and similarity to 8-amino-7-oxononoate synthase. Sequencing analysis and multiple alignment of the thymidine-adenine-cloned PCR amplicon revealed PLP-dependent family enzymes with specific confering codes and consensus amino acid residues specific to this group of functional proteins. Amino acid residues common to the majority of PLP-dependent enzymes were also revealed by the Lasergene MegAlign software. A phylogenetic tree was constructed. Its analysis revealed a close relationship of E. acetylicum to other bacteria isolated from extreme environments suggesting similarities in anabolic adaptability and evolutionary development.

scholarly journals Cysteine proteinases and cystatins

2003 ◽  
Vol 46 (1) ◽  
pp. 91-104 ◽  
Author(s):  
Adeliana S. Oliveira ◽  
José Xavier-Filho ◽  
Maurício P. Sales
Keyword(s):  
Amino Acid ◽  
Active Site ◽  
Defense Mechanisms ◽  
Enzyme Inhibitor ◽  
Cysteine Proteinase ◽  
Cysteine Proteinases ◽  
Amino Acid Residues ◽  
Protein Inhibitors ◽  
High Degree ◽  
Inhibitor Interaction

This review describeds the definition, localization, functions and examples of cysteine proteinases and their protein inhibitors in vertebrate, non-vertebrate animals and plants. These inhibitors are related with defense mechanisms of plant against pests. It also describes the factors involved in the specific cysteine proteinase-cystatin interaction and high degree of affinity and large specificity in this interaction which are not only represented by the compatibility between amino acid residues of the active site involved in catalysis, but also of all amino acid residues that participante in the enzyme-inhibitor interaction.

Amino acid sequence controls the self-assembled superstructure morphology of N-acetylated tri-β3-peptides

2015 ◽  
Vol 87 (9-10) ◽  
pp. 1021-1028 ◽  
Author(s):  
Rania S. Seoudi ◽  
Annette Dowd ◽  
Mark Del Borgo ◽  
Ketav Kulkarni ◽  
Patrick Perlmutter ◽  
...  
Keyword(s):  
Amino Acid ◽  
Self Assembly ◽  
Far Infrared ◽  
High Symmetry ◽  
Amino Acid Residues ◽  
Cross Sectional ◽  
Self Assembling ◽  
Afm Imaging ◽  
High Degree ◽  
Degree Of Similarity

AbstractPeptides based on unnatural β3-amino acids offer a versatile platform for the design of self-assembling nanostructures due to the folding stability of the 14-helix and the high symmetry of the side chains inherent in this geometry. We have previously described that N-terminal acetylation (Ac-) forms a supramolecular self-assembly motif that allows β3-peptides to assemble head-to-tail into a helical nanorod which then further bundles into hierarchical superstructures. Here we investigate the effect of the topography of the 14-helical nanorod on lateral self-assembly. Specifically, we report on the variations in the superstructure of three isomeric peptides comprising the same three β3-amino acid residues: β3-leucine (L), β3-isoleucine (I) β3-alanine (A) to give peptides Ac-β3[LIA], Ac-β3[IAL] and Ac-β3[ALI]. AFM imaging shows markedly different superstructures for the three peptides. Well defined synchrotron far-infrared spectra reveal uniform geometries with a high degree of similarity between the isomeric peptides in the amide modes of the 400–650 wavenumber range. Far-IR also confirms that the C-terminal carboxyl group is free in the assemblies, thus it is solvated in the dispersant. Hence, the differences in the superstructures formed by the fibers are defined primarily by van der Waals energy minimization between the varied cross sectional morphologies of the core nanorods.

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