| Autor: |
G. J. Sathisha, Y. K. Subrahmanya Prakash, V. B. Chachadi, N. N. Nagaraja, S. R. Inamdar, D. D. Leonidas, H. S. Savithri, B. M. Swamy |
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| Zdroj: |
Amino Acids; Aug2008, Vol. 35 Issue 2, p309-320, 12p |
| Abstrakt: |
Summary. X-ray crystallography, although a powerful technique for determining the three-dimensional structure of proteins, poses inherent problems in assigning the primary structure in residues Asp/Asn and Glu/Gln since these cannot be distinguished decisively in the electron density maps. In our recently published X-ray crystal structure of the Sclerotium rolfsii lectin (SRL) at 1.1 Å resolution, amino acid sequence was initially deduced from the electron density map and residues Asp/Asn and Glu/Gln were assigned by considering their hydrogen bonding potential within their structural neighborhood. Attempts to verify the sequence by Edman sequencing were not successful as the N terminus of the protein was blocked. Mass spectrometry was applied to verify and resolve the ambiguities in the SRL X-ray crystal structure deduced sequence. From the Matrix assisted laser desorption/ionization time-of-flight-mass spectrometry (MALDI TOF-MS) and liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) analysis of tryptic and chymotryptic peptides of SRL, we could confirm and correct the sequence at five locations with respect to Asp/Asn and Glu/Gln. Analysis data also confirmed the positions of Leu/Ile, Gln/Lys residues and the sequence covering 118 of the total 141 residues accounting to 83.68% of the earlier deduced sequence of SRL. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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