scholarly journals Primary structure of porcine spleen ribonuclease: sequence homology.

1997 ◽  
Vol 44 (4) ◽  
pp. 689-699 ◽  
Author(s):  
A Kusano ◽  
M Iwama ◽  
A Sanda ◽  
K Suwa ◽  
E Nakaizumi ◽  
...  

The primary structure of porcine spleen RNase (RNase Psp1) was investigated as a mean of assessing the structure-function relationship of base non-specific ribonucleases of animal origin. N-terminal analysis of RNase Psp1 yielded three N-terminal sequences. These peptides were separated by gel-filtration on Superdex 75HR, after reduction and S-carboxymethylation of RNase Psp1. Determination of the amino-acid sequence of these peptides indicated that the RNase Psp1 preparation consisted of three peptides having 20 (RCM RNase Psp1 pep1), 15 (RCM RNase Psp1 pep2), and 164 (RCM RNase Psp1 pro) amino-acid residues, respectively. It possessed two unique segments containing most of the active site amino-acid residues of the RNases of the RNase T2 family. The alignment of these three peptides in RNase Psp1 was determined by comparison with the other enzymes in the RNase T2 family. The overall results showed that RCM RNase Psp1 pep1 and RCM RNase Psp1 pep2 are derived from the N-terminal and C-terminal regions of RNase Psp1, respectively, probably by processing by some protease. The molecular mass of the protein moiety of RNase Psp1 was 23235 Da.

2020 ◽  
Author(s):  
Naoki Onoda ◽  
Yukihiro Hiramatsu ◽  
Shihono Teruya ◽  
Koichiro Suzuki ◽  
Yasuhiko Horiguchi

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.


1981 ◽  
Vol 46 (3) ◽  
pp. 807-816 ◽  
Author(s):  
Věra Jonáková ◽  
Dana Čechová ◽  
Otakar Mach

Cow colostrum contains three isoinhibitors A, B, and C, which are glycoproteins. In this study isoinhibitor A was isolated and characterized and the structure of its protein moiety compared with the known protein structures of isoinhibitors B and C. It was found that the primary structure of isoinhibitor A is identical with the primary structure of isoinhibitor B except that the C-terminus of its molecule is shorter by five amino acid residues. Four discrete chromatographic forms (I-IV) with different isoelectric points (pI 3.8 - I, 4.0 - II, 4.3 - III, and 4.5 - IV) were isolated by chromatography on SE-Sephadex, Form I is identical with isoinhibitor A. Forms II, III, and IV are represented by mixtures of isoinhibitors A, B, and C with a heterogeneous carbohydrate moiety which affects the total net charge of the individual inhibitor forms.


1973 ◽  
Vol 133 (4) ◽  
pp. 805-819 ◽  
Author(s):  
Francesco Bossa ◽  
Donatella Barra ◽  
Massimo Carloni ◽  
Paolo Fasella ◽  
Francesca Riva ◽  
...  

Peptides produced by thermolytic digestion of aminoethylated aspartate aminotransferase and of the oxidized enzyme were isolated and their amino acid sequences determined. Digestion by elastase of the carboxymethylated enzyme gave peptides representing approximately 40% of the primary structure. Fragments from these digests overlapped with previously reported sequences of peptides obtained by peptic and tryptic digestion (Doonan et al., 1972), giving ten composite peptides containing 395 amino acid residues. The amino acid composition of these composite peptides agrees well with that of the intact enzyme. Confirmatory results for some of the present data have been deposited as Supplementary Publication 50018 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973) 131, 5.


Plants ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 74 ◽  
Author(s):  
Eugene Rogozhin ◽  
Dmitry Ryazantsev ◽  
Alexey Smirnov ◽  
Sergey Zavriev

Cereal-derived bioactive peptides with antimicrobial activity have been poorly explored compared to those from dicotyledonous plants. Furthermore, there are a few reports addressing the structural differences between antimicrobial peptides (AMPs) from cultivated and wild cereals, which may shed light on significant varieties in the range and level of their antimicrobial activity. We performed a primary structure analysis of some antimicrobial peptides from wild and cultivated cereals to find out the features that are associated with the much higher antimicrobial resistance characteristic of wild plants. In this review, we identified and analyzed the main parameters determining significant antifungal activity. They relate to a high variability level in the sequences of C-terminal fragments and a high content of hydrophobic amino acid residues in the biologically active defensins in wild cereals, in contrast to AMPs from cultivated forms that usually exhibit weak, if any, activity. We analyzed the similarity of various physicochemical parameters between thionins and defensins. The presence of a high divergence on a fixed part of any polypeptide that is close to defensins could be a determining factor. For all of the currently known hevein-like peptides of cereals, we can say that the determining factor in this regard is the structure of the chitin-binding domain, and in particular, amino acid residues that are not directly involved in intermolecular interaction with chitin. The analysis of amino acid sequences of alpha-hairpinins (hairpin-like peptides) demonstrated much higher antifungal activity and more specificity of the peptides from wild cereals compared with those from wheat and corn, which may be associated with the presence of a mini cluster of positively charged amino acid residues. In addition, at least one hydrophobic residue may be responsible for binding to the components of fungal cell membranes.


2018 ◽  
Vol 52 (3) ◽  
pp. 478-487 ◽  
Author(s):  
D. A. Karasev ◽  
A. V. Veselovsky ◽  
A. A. Lagunin ◽  
D. A. Filimonov ◽  
B. N. Sobolev

2019 ◽  
Vol 24 (9) ◽  
pp. 928-938 ◽  
Author(s):  
Luca Palazzolo ◽  
Chiara Paravicini ◽  
Tommaso Laurenzi ◽  
Sara Adobati ◽  
Simona Saporiti ◽  
...  

SLC6A14 (ATB0,+) is a sodium- and chloride-dependent neutral and dibasic amino acid transporter that regulates the distribution of amino acids across cell membranes. The transporter is overexpressed in many human cancers characterized by an increased demand for amino acids; as such, it was recently acknowledged as a novel target for cancer therapy. The knowledge on the molecular mechanism of SLC6A14 transport is still limited, but some elegant studies on related transporters report the involvement of the 12 transmembrane α-helices in the transport mechanism, and describe structural rearrangements mediated by electrostatic interactions with some pivotal gating residues. In the present work, we constructed a SLC6A14 model in outward-facing conformation via homology modeling and used molecular dynamics simulations to predict amino acid residues critical for substrate recognition and translocation. We docked the proteinogenic amino acids and other known substrates in the SLC6A14 binding site to study both gating regions and the exposed residues involved in transport. Interestingly, some of these residues correspond to those previously identified in other LeuT-fold transporters; however, we could also identify a novel relevant residue with such function. For the first time, by combined approaches of molecular docking and molecular dynamics simulations, we highlight the potential role of these residues in neutral amino acid transport. This novel information unravels new aspects of the human SLC6A14 structure–function relationship and may have important outcomes for cancer treatment through the design of novel inhibitors of SLC6A14-mediated transport.


1971 ◽  
Vol 49 (9) ◽  
pp. 999-1004 ◽  
Author(s):  
M. C. Shaw ◽  
T. Viswanatha

The physicochemical properties of chymotrypsin-P obtained by the papain activation of chymotrypsinogen have been investigated. The molecular weight of this enzyme as determined by gel filtration technique has been found to be 24 000 ± 1000. The amino acid residues occupying the N-terminal positions and the composition of the B- and C-chains of chymotrypsin-P are identical with those found in α-chymotrypsin. Thus the difference between the two enzymes is restricted to the composition of their A-chains.


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