Amino Acid Residues ofEscherichia coliAcyl Carrier Protein Involved in Heterologous Protein Interactions†

Biochemistry ◽  
2003 ◽  
Vol 42 (1) ◽  
pp. 167-176 ◽  
Author(s):  
Lesa M. S. Worsham ◽  
Laurie Earls ◽  
Carrie Jolly ◽  
Keisha Gordon Langston ◽  
M. Stephen Trent ◽  
...  
2014 ◽  
Vol 13 (4) ◽  
pp. 539-547 ◽  
Author(s):  
VaNae Hamilton ◽  
Ujjal K. Singha ◽  
Joseph T. Smith ◽  
Ebony Weems ◽  
Minu Chaudhuri

ABSTRACTRecognition of mitochondrial targeting signals (MTS) by receptor translocases of outer and inner membranes of mitochondria is one of the prerequisites for import of nucleus-encoded proteins into this organelle. The MTS for a majority of trypanosomatid mitochondrial proteins have not been well defined. Here we analyzed the targeting signal for trypanosome alternative oxidase (TAO), which functions as the sole terminal oxidase in the infective form ofTrypanosoma brucei. Deleting the first 10 of 24 amino acids predicted to be the classical N-terminal MTS of TAO did not affect its import into mitochondriain vitro. Furthermore, ectopically expressed TAO was targeted to mitochondria in both forms of the parasite even after deletion of first 40 amino acid residues. However, deletion of more than 20 amino acid residues from the N terminus reduced the efficiency of import. These data suggest that besides an N-terminal MTS, TAO possesses an internal mitochondrial targeting signal. In addition, both the N-terminal MTS and the mature TAO protein were able to target a cytosolic protein, dihydrofolate reductase (DHFR), to aT. bruceimitochondrion. Further analysis identified a cryptic internal MTS of TAO, located within amino acid residues 115 to 146, which was fully capable of targeting DHFR to mitochondria. The internal signal was more efficient than the N-terminal MTS for import of this heterologous protein. Together, these results show that TAO possesses a cleavable N-terminal MTS as well as an internal MTS and that these signals act together for efficient import of TAO into mitochondria.


2003 ◽  
Vol 43 (supplement) ◽  
pp. S86
Author(s):  
T. Uno ◽  
Y. Hamabe ◽  
Y. Moriyama ◽  
Y. Tomisugi ◽  
Y. Ishikawa

2020 ◽  
Author(s):  
Bryan M. Zhao ◽  
Megan Hogan ◽  
Michael S Lee ◽  
Beverly K. Dyas ◽  
Robert G. Ulrich

ABSTRACTThe VH1 protein encoded by the highly conserved H1 locus of orthopoxviruses is a dual-specificity phosphatase (DUSPs) that hydrolyzes phosphate groups from phosphorylated tyrosine, serine, and threonine residues of viral and host cell proteins. Because the DUSP activities are required for virus replication, VH1 is a prime target for the development of therapeutic inhibitors. However, the presentation of a shallow catalytic site has thwarted all drug development efforts. As an alternative to direct targeting of catalytic pockets, we describe surface contacts between VH1 and substrates that are essential for full activity and provide a new pathway for developing inhibitors of protein-protein interactions. Critical amino acid residues were manipulated by site-directed mutagenesis of VH1, and perturbation of peptide substrate interactions based on these mutations were assessed by high-throughput assays that employed surface plasmon resonance and phosphatase activities. Two positively-charged residues (Lys-20 and Lys-22) and the hydrophobic side chain of Met-60 appear to orient the polarity of the pTyr peptide on the VH1 surface, while additional amino acid residues that flank the catalytic site contribute to substrate recognition and productive dephosphorylation. We propose that the enzyme-substrate contact residues described here may serve as molecular targets for the development of inhibitors that specifically block VH1 catalytic activity and thus poxvirus replication.


Author(s):  
João PGLM Rodrigues ◽  
Susana Barrera-Vilarmau ◽  
João MC Teixeira ◽  
Elizabeth Seckel ◽  
Panagiotis Kastritis ◽  
...  

AbstractSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the ongoing global pandemic that has infected more than 14 million people in more than 180 countries worldwide. Like other coronaviruses, SARS-CoV-2 is thought to have been transmitted to humans from wild animals. Given the scale and widespread geographical distribution of the current pandemic, the question emerges whether human-to-animal transmission is possible and if so, which animal species are most at risk. Here, we investigated the structural properties of several ACE2 orthologs bound to the SARS-CoV-2 spike protein. We found that species known not to be susceptible to SARS-CoV-2 infection have non-conservative mutations in several ACE2 amino acid residues that disrupt key polar and charged contacts with the viral spike protein. Our models also predict affinity-enhancing mutations that could be used to design ACE2 variants for therapeutic purposes. Finally, our study provides a blueprint for modeling viral-host protein interactions and highlights several important considerations when designing these computational studies and analyzing their results.


Biochemistry ◽  
2005 ◽  
Vol 44 (34) ◽  
pp. 11486-11495 ◽  
Author(s):  
Hong Feng ◽  
Liang Dong ◽  
Athena M. Klutz ◽  
Nima Aghaebrahim ◽  
Weiguo Cao

2004 ◽  
Vol 36 (2) ◽  
pp. 93-98 ◽  
Author(s):  
Gang Liu ◽  
Guang-Xiu Lu ◽  
Xiao-Wei Xing

Abstract Beginning from a mouse EST (GenBank accession No. BE644537) which was significantly up-regulated in cryptorchidism and represented a novel gene, we cloned a new gene (GenBank accession No. AY138810) which is related to apoptosis in human spermatogenic cells by means of GeneScan program and PCR technology. The gene whose full cDNA length is 1875 bp containing 8 exons and 7 introns is located in human chromosome 11q13.3. Its protein containing 316 amino acid residues is a new member of HSP40 protein family because the sequence contains the highly conserved J domain which is present in all DnaJ-like proteins and is considered to have a critical role in DnaJ-DnaK protein-protein interactions. TSARG6 protein displays a 45% identity in a 348-amino acid overlap with DJB5_HUMAN protein. The result of RT-PCR and Northern blot analysis showed that TSARG6 is specifically expressed in adult testis and the transcript is 1.8 kb. Based upon all these observations, it is considered that we cloned a new gene which probably inhibited human testis spermatogenesis apoptosis.


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