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Structural and functional analysis of "non-smelly" proteins
Jing Yan1, Jianlin Cheng2, Lukasz Kurgan3
1Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada.
Cellular and Molecular Life Sciences : CMLS
|September 6, 2019
Summary
Proteins lacking cysteine (C-depleted) or cysteine and aromatic residues (CFYWH-depleted) are rare and often disordered. These "non-smelly" proteins primarily function in complexes, highlighting the importance of specific residues for protein structure.
Area of Science:
- Biochemistry
- Structural Biology
- Bioinformatics
Background:
- Cysteine and aromatic residues are crucial for protein structure.
- Understanding proteins with depleted structural residues provides insights into protein folding and function.
Purpose of the Study:
- To investigate the prevalence, structural characteristics, and functions of proteins depleted in cysteine (C-depleted) and cysteine/aromatic residues (CFYWH-depleted) across diverse proteomes.
- To explore the relationship between residue depletion, intrinsic disorder, and protein function.
Main Methods:
- Bioinformatic analysis of 817 proteomes from all domains of life.
- Assessment of protein abundance, structural coverage (using Protein Data Bank - PDB), and functional annotations.
- Correlation analysis between residue composition and intrinsic disorder levels.
Main Results:
- C-depleted proteins are abundant, particularly in prokaryotes, while CFYWH-depleted proteins are rare (approx. 0.05%) and virtually absent from the PDB.
- Depletion of cysteine and aromatic residues correlates with increased intrinsic disorder across all life domains.
- Organisms with higher C-depleted protein levels exhibit greater intrinsic disorder and lower structural coverage.
- These proteins often function in nucleic acid-interacting complexes (ribosomes, nucleosomes) and are involved in processes like translation and transcription.
Conclusions:
- Protein structure is significantly influenced by the presence of cysteine and aromatic residues.
- "Non-smelly" proteins, characterized by intrinsic disorder, typically fold through interactions with nucleic acids rather than forming independent monomeric structures.
- The study reveals the functional roles and structural properties of proteins with limited cysteine and aromatic residues, offering insights into the fundamental principles of protein structure and function.