排序方式: 共有3条查询结果,搜索用时 15 毫秒
1
1.
Christopher A. MacRaild Milan Zachrdla Dean Andrew Bankala Krishnarjuna Ji?í Nová?ek Luká? ?ídek Vladimír Sklená? Jack S. Richards James G. Beeson Robin F. Anders Raymond S. Norton 《PloS one》2015,10(3)
Merozoite surface protein 2 (MSP2) of Plasmodium falciparum is an abundant, intrinsically disordered protein that is GPI-anchored to the surface of the invasive blood stage of the malaria parasite. Recombinant MSP2 has been trialled as a component of a malaria vaccine, and is one of several disordered proteins that are candidates for inclusion in vaccines for malaria and other diseases. Nonetheless, little is known about the implications of protein disorder for the development of an effective antibody response. We have therefore undertaken a detailed analysis of the conformational dynamics of the two allelic forms of MSP2 (3D7 and FC27) using NMR spectroscopy. Chemical shifts and NMR relaxation data indicate that conformational and dynamic properties of the N- and C-terminal conserved regions in the two forms of MSP2 are essentially identical, but significant variation exists between and within the central variable regions. We observe a strong relationship between the conformational dynamics and the antigenicity of MSP2, as assessed with antisera to recombinant MSP2. Regions of increased conformational order in MSP2, including those in the conserved regions, are more strongly antigenic, while the most flexible regions are minimally antigenic. This suggests that modifications that increase conformational order may offer a means to tune the antigenicity of MSP2 and other disordered antigens, with implications for vaccine design. 相似文献
2.
Krishnarjuna B Jaipuria G Thakur A D'Silva P Atreya HS 《Journal of biomolecular NMR》2011,49(1):39-51
Sequence specific resonance assignment constitutes an important step towards high-resolution structure determination of proteins
by NMR and is aided by selective identification and assignment of amino acid types. The traditional approach to selective
labeling yields only the chemical shifts of the particular amino acid being selected and does not help in establishing a link
between adjacent residues along the polypeptide chain, which is important for sequential assignments. An alternative approach
is the method of amino acid selective ‘unlabeling’ or reverse labeling, which involves selective unlabeling of specific amino
acid types against a uniformly 13C/15N labeled background. Based on this method, we present a novel approach for sequential assignments in proteins. The method
involves a new NMR experiment named, {12CO
i
–15N
i+1}-filtered HSQC, which aids in linking the 1HN/15N resonances of the selectively unlabeled residue, i, and its C-terminal neighbor, i + 1, in HN-detected double and triple resonance spectra. This leads to the assignment of a tri-peptide segment from the knowledge
of the amino acid types of residues: i − 1, i and i + 1, thereby speeding up the sequential assignment process. The method has the advantage of being relatively inexpensive,
applicable to 2H labeled protein and can be coupled with cell-free synthesis and/or automated assignment approaches. A detailed survey involving
unlabeling of different amino acid types individually or in pairs reveals that the proposed approach is also robust to misincorporation
of 14N at undesired sites. Taken together, this study represents the first application of selective unlabeling for sequence specific
resonance assignments and opens up new avenues to using this methodology in protein structural studies. 相似文献
3.
B.?Krishnarjuna Anjali?D.?Ganjiwale Uma?V.?ManjapparaEmail author S.?RaghothamaEmail author 《International journal of peptide research and therapeutics》2011,17(4):259-270
Obestatin is a more recently discovered hormone that is encoded by the ghrelin gene and produced in the stomach and gut. We
report NMR analysis on synthetic Obestatin (OB23), a 23 residue peptide, along with three overlapping fragments of the same
in methanol solvent as a first step towards structure activity relationship. Selective substitutions on the promising N-terminal
and middle fragments of obestatin have been carried out in order to improve the efficacy and potency. In the N-terminal fragment
two peptides were obtained by the replacement of Gly (8) with α-aminoisobutyric acid (Aib, U) and Phe (F5) with Cyclohexylalanine
(Cha). In case of the middle fragment both Gly (3) and Gly (8) were replaced with Aib residues. The rationale being, these
unusual amino acids could provide protection from immediate degradation and aid structure stabilization. Our previous studies
showed that the N-terminal and the middle fragment were unstructured and hence this substitution would directly evaluate the
effect of structure on the activity of these fragment analogs. Detailed NMR analysis clearly demonstrates formation of helical
secondary structure in all the peptide analogues and provides justification for relative activities reported by our group
previously (Nagaraj et al. 2009). 相似文献
1