5XE4

NMR solution structure of the aromatic mutant H43W H67F cytochrome b5

Summary for 5XE4

• Entry DOI: 10.2210/pdb5xe4/pdb
• Related: 5XEE
• NMR Information: BMRB: 36070
• Descriptor: Cytochrome b5 (1 entity in total)
• Functional Keywords: aromatic interactions protein folding, electron transport
• Biological source: Rattus norvegicus (Rat)
• Cellular location: Endoplasmic reticulum membrane; Single-pass membrane protein; Cytoplasmic side: P00173
• Total number of polymer chains: 1
• Total formula weight: 11314.47

Authors

Balakrishnan, S.,Sarma, S.P. (deposition date: 2017-03-31, release date: 2018-02-14, Last modification date: 2024-05-15)

Primary citation

Balakrishnan, S.,Sarma, S.P.
Engineering Aromatic-Aromatic Interactions To Nucleate Folding in Intrinsically Disordered Regions of Proteins
Biochemistry, 56:4346-4359, 2017

PubMed Abstract: Aromatic interactions are an important force in protein folding as they combine the stability of a hydrophobic interaction with the selectivity of a hydrogen bond. Much of our understanding of aromatic interactions comes from "bioinformatics" based analyses of protein structures and from the contribution of these interactions to stabilizing secondary structure motifs in model peptides. In this study, the structural consequences of aromatic interactions on protein folding have been explored in engineered mutants of the molten globule protein apo-cytochrome b. Structural changes from disorder to order due to aromatic interactions in two variants of the protein, viz., WF-cytb5 and FF-cytb5, result in significant long-range secondary and tertiary structure. The results show that 54 and 52% of the residues in WF-cytb5 and FF-cytb5, respectively, occupy ordered regions versus 26% in apo-cytochrome b. The interactions between the aromatic groups are offset-stacked and edge-to-face for the Trp-Phe and Phe-Phe mutants, respectively. Urea denaturation studies indicate that both mutants have a C higher than that of apo-cytochrome b and are more stable to chaotropic agents than apo-cytochrome b. The introduction of these aromatic residues also results in "trimer" interactions with existing aromatic groups, reaffirming the selectivity of the aromatic interactions. These studies provide insights into the aromatic interactions that drive disorder-to-order transitions in intrinsically disordered regions of proteins and will aid in de novo protein design beyond small peptide scaffolds.

PubMed: 28738155
DOI: 10.1021/acs.biochem.7b00437

Experimental method

SOLUTION NMR