Comparison of the folding processes of distantly related proteins. Importance of hydrophobic content in folding.


Abstract

The N-terminal domain of HypF from Escherichia coli (HypF-N) is a 91 residue protein module sharing the same folding topology and a significant sequence identity with two extensively studied human proteins, muscle and common-type acylphosphatases (mAcP and ctAcP). With the aim of learning fundamental aspects of protein folding from the close comparison of so similar proteins, the folding process of HypF-N has been studied using stopped-flow fluorescence. While mAcP and ctAcP fold in a two-state fashion, HypF-N was found to collapse into a partially folded intermediate before reaching the fully folded conformation. Formation of a burst-phase intermediate is indicated by the roll over in the Chevron plot at low urea concentrations and by the large jump of intrinsic and 8-anilino-1-naphtalenesulphonic acid-derived fluorescence immediately after removal of denaturant. Furthermore, HypF-N was found to fold rapidly with a rate constant that is approximately two and three orders of magnitudes faster than ctAcP and mAcP, respectively. Differences between the bacterial protein and the two human counterparts were also found as to the involvement of proline isomerism in their respective folding processes. The results clearly indicate that features that are often thought to be relevant in protein folding are not highly conserved in the evolution of the acylphosphatase superfamily. The large difference in folding rate between mAcP and HypF-N cannot be entirely accounted for by the difference in relative contact order or related topological metrics. The analysis shows that the higher folding rate of HypF-N is in part due to the relatively high hydrophobic content of this protein. This conclusion, which is also supported by the highly significant correlation found between folding rate and hydrophobic content within a group of proteins displaying the topology of HypF-N and AcPs, suggests that the average hydrophobicity of a protein sequence is an important determinant of its folding rate. Study holds ProTherm entries: 16271 Extra Details: (i) N-terminal domain,(ii) 2mM DTT was added in the experiment. folding; topology; acylphosphatase; hydrophobicity; evolution

Submission Details

ID: d8k3YqRQ4

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:47 p.m.

Version: 1

Publication Details
Calloni G;Taddei N;Plaxco KW;Ramponi G;Stefani M;Chiti F,J. Mol. Biol. (2003) Comparison of the folding processes of distantly related proteins. Importance of hydrophobic content in folding. PMID:12842473
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P
 

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)


Relevant PDB Entries

Structure ID Release Date Resolution Structure Title
1GXT 2002-09-12 1.27 Hydrogenase Maturation Protein HypF 'acylphosphatase-like' N-terminal domain (HypF-ACP) in complex with Sulfate
1GXU 2002-09-12 1.27 Hydrogenase Maturation Protein HypF 'acylphosphatase-like' N-terminal domain (HypF-ACP) in complex with a substrate. Crystal grown in the presence of carbamoylphosphate

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Carbamoyltransferase HypF P30131 HYPF_ECOLI