scholarly journals The C-terminal domain of dimeric serine hydroxymethyltransferase plays a key role in stabilization of the quaternary structure and cooperative unfolding of protein: Domain swapping studies with enzymes having high sequence identity

2004 ◽  
Vol 13 (8) ◽  
pp. 2184-2195 ◽  
Author(s):  
Anant Narayan Bhatt ◽  
M. Yahiya Khan ◽  
Vinod Bhakuni
Keyword(s):  
Quaternary Structure ◽  
Serine Hydroxymethyltransferase ◽  
Domain Swapping ◽  
Protein Domain ◽  
High Sequence Identity ◽  
Sequence Identity ◽  
Terminal Domain

HACRE1, a recently inserted copia-like retrotransposon of sunflower (Helianthus annuus L.)

Genome ◽  
2009 ◽  
Vol 52 (11) ◽  
pp. 904-911 ◽  
Author(s):  
M. Buti ◽  
T. Giordani ◽  
M. Vukich ◽  
L. Gentzbittel ◽  
L. Pistelli ◽  
...  
Keyword(s):  
Helianthus Annuus ◽  
Sequence Similarity ◽  
Protein Domain ◽  
Long Terminal Repeats ◽  
High Sequence Identity ◽  
Nonsense Mutations ◽  
Reading Frame ◽  
Sequence Identity ◽  
Isolation And Characterization ◽  
Copia Retrotransposon

In this paper we report on the isolation and characterization, for the first time, of a complete 6511 bp retrotransposon of sunflower. Considering its protein domain order and sequence similarity to other copia elements of dicotyledons, this retrotransposon was assigned to the copia retrotransposon superfamily and named HACRE1 ( Helianthus annuus copia-like retroelement 1). HACRE1 carries 5′ and 3′ long terminal repeats (LTRs) flanking an internal region of 4661 bp. The LTRs are identical in their sequence except for two deletions of 7 and 5 nucleotides in the 5′ LTR. Based on the sequence identity of the LTRs, HACRE1 was estimated to have inserted within the last ∼84 000 years. The isolated sequence contains a complete open reading frame with only one complete reading frame. The absence of nonsense mutations agrees with the very high sequence identity between LTRs, confirming that HACRE1 insertion is recent. The haploid genome of sunflower (inbred line HCM) contains about 160 copies of HACRE1. This retrotransposon is expressed in leaflets from 7-day-old plantlets under different light conditions, probably in relation to the occurrence of many putative light-related regulatory cis-elements in the LTRs. However, sequenced cDNAs show less variability than HACRE1 genomic sequences, indicating that only a subset of this family is expressed under these conditions.

scholarly journals Turkey and chicken interferon-γ, which share high sequence identity, are biologically cross-reactive

2001 ◽  
Vol 25 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Shelly Lawson ◽  
Lisa Rothwell ◽  
Benedicte Lambrecht ◽  
Ken Howes ◽  
K. Venugopal ◽  
...  
Keyword(s):  
Interferon Γ ◽  
High Sequence Identity ◽  
Sequence Identity

Structure of the N-terminal domain of Euprosthenops australis dragline silk suggests that conversion of spidroin dope to spider silk involves a conserved asymmetric dimer intermediate

2019 ◽  
Vol 75 (7) ◽  
pp. 618-627 ◽  
Author(s):  
Wangshu Jiang ◽  
Glareh Askarieh ◽  
Alexander Shkumatov ◽  
My Hedhammar ◽  
Stefan D. Knight
Keyword(s):  
Electrostatic Interactions ◽  
Spider Silk ◽  
Quaternary Structure ◽  
Nephila Clavipes ◽  
Trigger Mechanism ◽  
Dragline Silk ◽  
Terminal Domain ◽  
Structure Changes ◽  
Molecular Events ◽  
Asymmetric Dimer

Spider silk is a biomaterial with exceptional mechanical toughness, and there is great interest in developing biomimetic methods to produce engineered spider silk-based materials. However, the mechanisms that regulate the conversion of spider silk proteins (spidroins) from highly soluble dope into silk are not completely understood. The N-terminal domain (NT) of Euprosthenops australis dragline silk protein undergoes conformational and quaternary-structure changes from a monomer at a pH above 7 to a homodimer at lower pH values. Conversion from the monomer to the dimer requires the protonation of three conserved glutamic acid residues, resulting in a low-pH `locked' dimer stabilized by symmetric electrostatic interactions at the poles of the dimer. The detailed molecular events during this transition are still unresolved. Here, a 2.1 Å resolution crystal structure of an NT T61A mutant in an alternative, asymmetric, dimer form in which the electrostatic interactions at one of the poles are dramatically different from those in symmetrical dimers is presented. A similar asymmetric dimer structure from dragline silk of Nephila clavipes has previously been described. It is suggested that asymmetric dimers represent a conserved intermediate state in spider silk formation, and a revised `lock-and-trigger' mechanism for spider silk formation is presented.

scholarly journals Structure-based group A streptococcal vaccine design: Helical wheel homology predicts antibody cross-reactivity among streptococcal M protein–derived peptides

2020 ◽  
Vol 295 (12) ◽  
pp. 3826-3836 ◽  
Author(s):  
Michelle P. Aranha ◽  
Thomas A. Penfound ◽  
Jay A. Spencer ◽  
Rupesh Agarwal ◽  
Jerome Baudry ◽  
...  
Keyword(s):  
Group A Streptococcus ◽  
Coiled Coil ◽  
Cross Reactivity ◽  
M Protein ◽  
High Sequence Identity ◽  
Sequence Identity ◽  
Streptococcal M Protein ◽  
Helical Wheel ◽  
Group A ◽  
Immunological Assays

Group A streptococcus (Strep A) surface M protein, an α-helical coiled-coil dimer, is a vaccine target and a major determinant of streptococcal virulence. The sequence-variable N-terminal region of the M protein defines the M type and also contains epitopes that promote opsonophagocytic killing of streptococci. Recent reports have reported considerable cross-reactivity among different M types, suggesting the prospect of identifying cross-protective epitopes that would constitute a broadly protective multivalent vaccine against Strep A isolates. Here, we have used a combination of immunological assays, structural biology, and cheminformatics to construct a recombinant M protein–based vaccine that included six Strep A M peptides that were predicted to elicit antisera that would cross-react with an additional 15 nonvaccine M types of Strep A. Rabbit antisera against this recombinant vaccine cross-reacted with 10 of the 15 nonvaccine M peptides. Two of the five nonvaccine M peptides that did not cross-react shared high sequence identity (≥50%) with the vaccine peptides, implying that high sequence identity alone was insufficient for cross-reactivity among the M peptides. Additional structural analyses revealed that the sequence identity at corresponding polar helical-wheel heptad sites between vaccine and nonvaccine peptides accurately distinguishes cross-reactive from non–cross-reactive peptides. On the basis of these observations, we developed a scoring algorithm based on the sequence identity at polar heptad sites. When applied to all epidemiologically important M types, this algorithm should enable the selection of a minimal number of M peptide–based vaccine candidates that elicit broadly protective immunity against Strep A.

scholarly journals Molecular Changes in Dengue Envelope Protein Domain III upon Interaction with Glycosaminoglycans

Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 935
Author(s):  
James G. Hyatt ◽  
Sylvain Prévost ◽  
Juliette M. Devos ◽  
Courtney J. Mycroft-West ◽  
Mark A. Skidmore ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Envelope Protein ◽  
Quaternary Structure ◽  
Chondroitin Sulphate ◽  
Viral Envelope ◽  
Protein Domain ◽  
Viral Envelope Protein ◽  
Oligomeric State ◽  
Molecular Changes ◽  
Viral Attachment

Dengue fever is a rapidly emerging vector-borne viral disease with a growing global burden of approximately 390 million new infections per annum. The Dengue virus (DENV) is a flavivirus spread by female mosquitos of the aedes genus, but the mechanism of viral endocytosis is poorly understood at a molecular level, preventing the development of effective transmission blocking vaccines (TBVs). Recently, glycosaminoglycans (GAGs) have been identified as playing a role during initial viral attachment through interaction with the third domain of the viral envelope protein (EDIII). Here, we report a systematic study investigating the effect of a range of biologically relevant GAGs on the structure and oligomeric state of recombinantly generated EDIII. We provide novel in situ biophysical evidence that heparin and chondroitin sulphate C induce conformational changes in EDIII at the secondary structure level. Furthermore, we report the ability of chondroitin sulphate C to bind EDIII and induce higher-order dynamic molecular changes at the tertiary and quaternary structure levels which are dependent on pH, GAG species, and the GAG sulphation state. Lastly, we conducted ab initio modelling of Small Angle Neutron Scattering (SANS) data to visualise the induced oligomeric state of EDIII caused by interaction with chondroitin sulphate C, which may aid in TBV development.

The C-terminal domain of Escherichia coli dihydrodipicolinate synthase (DHDPS) is essential for maintenance of quaternary structure and efficient catalysis

2009 ◽  
Vol 380 (4) ◽  
pp. 802-806 ◽  
Author(s):  
Belinda B.B. Guo ◽  
Sean R.A. Devenish ◽  
Renwick C.J. Dobson ◽  
Andrew C. Muscroft-Taylor ◽  
Juliet A. Gerrard
Keyword(s):  
Escherichia Coli ◽  
Quaternary Structure ◽  
Dihydrodipicolinate Synthase ◽  
Terminal Domain
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