scholarly journals In vitro Protein Transport into Chloroplasts by a Transit Peptide of Glutamine Synthetase

1995 ◽  
Vol 69 (5) ◽  
pp. 565-567
Author(s):  
Takahiko Hayakawa ◽  
Tadaka Nakajima
2006 ◽  
Vol 188 (1) ◽  
pp. 335-338 ◽  
Author(s):  
Lucia B. Jilaveanu ◽  
Donald Oliver

ABSTRACT SecA facilitates protein transport across the eubacterial plasma membrane by its association with cargo proteins and the SecYEG translocon, followed by ATP-driven conformational changes that promote protein translocation in a stepwise manner. Whether SecA functions as a monomer or a dimer during this process has been the subject of considerable controversy. Here we utilize cysteine-directed mutagenesis along with the crystal structure of the SecA dimer to create a cross-linked dimer at its subunit interface, which was normally active for in vitro protein translocation.


2019 ◽  
Vol 26 (5) ◽  
pp. 339-347 ◽  
Author(s):  
Dilani G. Gamage ◽  
Ajith Gunaratne ◽  
Gopal R. Periyannan ◽  
Timothy G. Russell

Background: The dipeptide composition-based Instability Index (II) is one of the protein primary structure-dependent methods available for in vivo protein stability predictions. As per this method, proteins with II value below 40 are stable proteins. Intracellular protein stability principles guided the original development of the II method. However, the use of the II method for in vitro protein stability predictions raises questions about the validity of applying the II method under experimental conditions that are different from the in vivo setting. Objective: The aim of this study is to experimentally test the validity of the use of II as an in vitro protein stability predictor. Methods: A representative protein CCM (CCM - Caulobacter crescentus metalloprotein) that rapidly degrades under in vitro conditions was used to probe the dipeptide sequence-dependent degradation properties of CCM by generating CCM mutants to represent stable and unstable II values. A comparative degradation analysis was carried out under in vitro conditions using wildtype CCM, CCM mutants and two other candidate proteins: metallo-β-lactamase L1 and α -S1- casein representing stable, borderline stable/unstable, and unstable proteins as per the II predictions. The effect of temperature and a protein stabilizing agent on CCM degradation was also tested. Results: Data support the dipeptide composition-dependent protein stability/instability in wt-CCM and mutants as predicted by the II method under in vitro conditions. However, the II failed to accurately represent the stability of other tested proteins. Data indicate the influence of protein environmental factors on the autoproteolysis of proteins. Conclusion: Broader application of the II method for the prediction of protein stability under in vitro conditions is questionable as the stability of the protein may be dependent not only on the intrinsic nature of the protein but also on the conditions of the protein milieu.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Haifeng C. Xu ◽  
Ruifeng Wang ◽  
Prashant V. Shinde ◽  
Lara Walotka ◽  
Anfei Huang ◽  
...  

AbstractImmune evasion of pathogens can modify the course of infection and impact viral persistence and pathology. Here, using different strains of the lymphocytic choriomeningitis virus (LCMV) model system, we show that slower propagation results in limited type I interferon (IFN-I) production and viral persistence. Specifically, cells infected with LCMV-Docile exhibited reduced viral replication when compared to LCMV-WE and as a consequence, infection with LCMV-Docile resulted in reduced activation of bone marrow derived dendritic cells (BMDCs) and IFN-I production in vitro in comparison with LCMV-WE. In vivo, we observed a reduction of IFN-I, T cell exhaustion and viral persistence following infection of LCMV-Docile but not LCMV-WE. Mechanistically, block of intracellular protein transport uncovered reduced propagation of LCMV-Docile when compared to LCMV-WE. This reduced propagation was critical in blunting the activation of the innate and adaptive immune system. When mice were simultaneously infected with LCMV-Docile and LCMV-WE, immune function was restored and IFN-I production, T cell effector functions as well as viral loads were similar to that of mice infected with LCMV-WE alone. Taken together, this study suggests that reduced viral propagation can result in immune evasion and viral persistence.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Benedikt Frieg ◽  
Boris Görg ◽  
Holger Gohlke ◽  
Dieter Häussinger

Abstract Glutamine synthetase (GS) in the liver is expressed in a small perivenous, highly specialized hepatocyte population and is essential for the maintenance of low, non-toxic ammonia levels in the organism. However, GS activity can be impaired by tyrosine nitration of the enzyme in response to oxidative/nitrosative stress in a pH-sensitive way. The underlying molecular mechanism as investigated by combined molecular simulations and in vitro experiments indicates that tyrosine nitration can lead to a fully reversible and pH-sensitive regulation of protein function. This approach was also used to understand the functional consequences of several recently described point mutations of human GS with clinical relevance and to suggest an approach to restore impaired GS activity.


PLoS ONE ◽  
2009 ◽  
Vol 4 (4) ◽  
pp. e5185 ◽  
Author(s):  
A. Sesilja Aranko ◽  
Sara Züger ◽  
Edith Buchinger ◽  
Hideo Iwaï

2012 ◽  
Vol 60 (20) ◽  
pp. 5071-5075 ◽  
Author(s):  
Martin M. Lorenz ◽  
Christine Hayot Carbonero ◽  
Lydia Smith ◽  
Peter Udén

1976 ◽  
Vol 22 (2) ◽  
pp. 304-308
Author(s):  
C. T. Chow

An active in vitro protein-synthesizing system has been developed from Rhodospirillum rubrum grown under either photosynthetic or heterotrophic conditions. A protease activity has been found in both of these systems, and this activity can be readily inactivated by treating the cells with KCl and phenylmethyl sulfonylfluoride. The difference in protein-synthesizing activity between the photosynthetic and the heterotrophic systems has been tested in regard to the requirement of various chemicals and the response to protein synthesis inhibitors or various chemical compounds. It has been concluded that only minor differences in protein-synthesizing activity exist between these two systems.


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