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Title: Structure of an artificial chimaeric protein domain
Author: de Bono, S.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2004
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This work describes the structure of an artificial chimaeric protein, 1B11, generated by non-homogeneous recombination between a defined gene fragment coding for the N-terminal half of E. coli cold shock protein (CspA), and a randomly selected C-terminal portion. The N-terminal segment of 1B11 consists of the first 36 residues of CspA, which forms three antiparallel beta strands. The termination point of this structural entity corresponds to a well conserved exon boundary in eukaryotic homologs of CspA. The C-terminal segment of 1B11 is derived fro the first 34 residues of the E. coli 30S ribosomal S1 domain. Both CspA and the S1 domain are monomeric globular proteins and have a five stranded beta barrel topology. 1B11 not only is tetrameric, but also has a different architecture, composed of a six-stranded beta barrel in which two strands are domain swapped. The individual segments taken from the original structures, have, however, retained much the same topology. The overall OB-fold topology is well maintained, with the first three strands of 1B11 being superimposable with those of CspA. Two strands from the C-terminal half of 1B11 have come to occupy spatially similar positions to the fourth and fifth strand of CspA. Also, hydrophobic residues in the 1B11 barrel core recapitulate barrel packing in the original structure. The sixth strand of 1B11 has been accommodated at the periphery of the barrel, such that a number of hydrophobic residues are solvent exposed. Oligomerisation in the form of tetramer formation and domain swapping allows stabilization of the structure by burying those hydrophobic residues. A combination of two non-contiguous subdomain elements has given rise to a folded domain with novel architecture and composition. This is consistent with the creation of domains by exon shuffling early on in evolution.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available