Faculty Opinions recommendation of NMR structures of two designed proteins with high sequence identity but different fold and function.

2008 ◽  
Author(s):  
H Jane Dyson ◽  
Gira Bhabha
Keyword(s):  
High Sequence Identity ◽  
Sequence Identity ◽  
Nmr Structures ◽  
Designed Proteins ◽  
And Function

scholarly journals Structure and antimicrobial activity of NCR169, a nodule-specific cysteine-rich peptide of Medicago truncatula

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Noriyoshi Isozumi ◽  
Yuya Masubuchi ◽  
Tomohiro Imamura ◽  
Masashi Mori ◽  
Hironori Koga ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Medicago Truncatula ◽  
Mechanism Of Action ◽  
Disulfide Bonds ◽  
Sinorhizobium Meliloti ◽  
Bound State ◽  
Disulfide Linkage ◽  
Model Legume ◽  
Nmr Structures ◽  
And Function

AbstractA model legume, Medicago truncatula, has over 600 nodule-specific cysteine-rich (NCR) peptides required for symbiosis with rhizobia. Among them, NCR169, an essential factor for establishing symbiosis, has four cysteine residues that are indispensable for its function. However, knowledge of NCR169 structure and mechanism of action is still lacking. In this study, we solved two NMR structures of NCR169 caused by different disulfide linkage patterns. We show that both structures have a consensus C-terminal β-sheet attached to an extended N-terminal region with dissimilar features; one moves widely, whereas the other is relatively stapled. We further revealed that the disulfide bonds of NCR169 contribute to its structural stability and solubility. Regarding the function, one of the NCR169 oxidized forms could bind to negatively charged bacterial phospholipids. Furthermore, the positively charged lysine-rich region of NCR169 may be responsible for its antimicrobial activity against Escherichia coli and Sinorhizobium meliloti. This active region was disordered even in the phospholipid bound state, suggesting that the disordered conformation of this region is key to its function. Morphological observations suggested the mechanism of action of NCR169 on bacteria. The present study on NCR169 provides new insights into the structure and function of NCR peptides.

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

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 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.

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