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Related Concept Videos

Protein and Protein Structure02:15

Protein and Protein Structure

Proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules. Proteins may be structural, regulatory, contractile, or protective. They may serve in transport, storage, or membranes; or they may be toxins or enzymes. Their structures, like their functions, vary greatly. They are all, however, amino acid polymers arranged in a linear sequence.
A protein's shape is critical to its function. For example, an enzyme can...
Protein Organization01:13

Protein Organization

Overview
Protein Organization01:24

Protein Organization

Proteins are polymers of amino acid residues. They are versatile and responsible for different cellular functions, including DNA replication, molecular transport, catalysis, and structural support. Proteins have a hierarchical structure comprising at least three levels of organization: primary, secondary, and tertiary structure. Some large proteins have a quaternary structure where individual protein subunits are linked together.
The primary structure of a protein is its amino acid sequence.
Protein Organization01:13

Protein Organization

Overview
Protein Organization01:24

Protein Organization

Proteins are polymers of amino acid residues. They are versatile and responsible for different cellular functions, including DNA replication, molecular transport, catalysis, and structural support. Proteins have a hierarchical structure comprising at least three levels of organization: primary, secondary, and tertiary structure. Some large proteins have a quaternary structure where individual protein subunits are linked together.
The primary structure of a protein is its amino acid sequence.
Protein Folding01:22

Protein Folding

Overview

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Residue-Specific Exchange of Proline by Proline Analogs in Fluorescent Proteins: How "Molecular Surgery" of the Backbone Affects Folding and Stability
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Polyproline-II helix in proteins: structure and function.

Alexei A Adzhubei1, Michael J E Sternberg, Alexander A Makarov

  • 1Engelhard Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow 119991, Russia. alexei.adzhubei@eimb.ru

Journal of Molecular Biology
|March 20, 2013
PubMed
Summary
This summary is machine-generated.

The poly-proline type II (PPII) helix is a key protein structure found in both folded and unfolded proteins. This review explores PPII helices in various proteins and their crucial roles in biological functions.

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Area of Science:

  • Protein structure and dynamics
  • Biophysics
  • Molecular biology

Background:

  • The poly-proline type II (PPII) helix is a significant structural motif in proteins.
  • While less common than alpha-helices and beta-structures in folded proteins, PPII helices are prevalent in unfolded proteins and collagen.
  • PPII helices are increasingly recognized for their roles beyond structural integrity.

Purpose of the Study:

  • To provide a comprehensive overview of the poly-proline type II (PPII) helix.
  • To discuss the occurrence and significance of PPII helices in unfolded and folded proteins.
  • To elucidate the functional implications of PPII helices in various biological processes.

Main Methods:

  • Literature review and synthesis of existing research on PPII helices.
  • Analysis of spectroscopic data identifying PPII structures in proteins.
  • Examination of protein-protein and protein-nucleic acid interactions involving PPII motifs.

Main Results:

  • PPII helices are a distinct structural class found in fibrillar, folded, and unfolded proteins.
  • Natively unfolded proteins exhibit a high content of PPII helices, identifiable via spectroscopy.
  • PPII structures are crucial for protein interactions, signal transduction, and complex assembly, notably in SH3 domains.

Conclusions:

  • PPII helices play vital roles in transcription, cell motility, self-assembly, and pathogenesis.
  • Despite their functional importance, PPII helices are often overlooked in experimental structures and modeling.
  • Further investigation into PPII helices is essential for a complete understanding of protein structure-function relationships.