Translation and Protein Folding

Vocabulary flashcards covering protein biosynthesis, hierarchy of protein structure, Henderson-Hasselbalch applications, molecular chaperones, and diseases associated with protein misfolding including Alzheimer's, Prion diseases, and Amyloidosis.

$A\beta$ (Amyloid-beta)

A protein involved in neuronal signaling and synaptic plasticity that, when misfolded due to abnormal secretase function, aggregates and forms plaques in Alzheimer’s Disease.

Tau

A protein that binds to microtubules in axons to improve assembly and stability; over-phosphorylation leads to its release and aggregation into NFT or HMW.

NFT

Neurofibrillary tangles, which are aggregates of over-phosphorylated Tau protein.

HMW

High molecular weight Tau aggregates.

Aliphatic Amino Acids

Nonpolar R-groups including Glycine, Alanine, Valine, Leucine, Isoleucine, and Proline.

Aromatic Amino Acids

Amino acids with nonpolar ring structures: Phenylalanine, Tyrosine, and Tryptophan.

Acidic Amino Acids

Negatively charged amino acids at physiologic pH, including Aspartic acid ($pK_a \text{ 3.71}$) and Glutamic acid ($pK_a \text{ 4.15}$).

Basic Amino Acids

Positively charged amino acids at physiologic pH, including Lysine ($pK_a \text{ 10.67}$), Arginine ($pK_a \text{ 12.10}$), and Histidine ($pK_a \text{ 6.04}$).

Henderson-Hasselbalch Equation

$pH = pK_a + \text{log}_{10} \frac{[\text{A}^-]}{[\text{HA}]}$, used to determine the dissociation of an acid.

Primary Structure

The sequence of amino acids in a polypeptide chain formed by peptide bonds between amino and carboxy groups.

Secondary Structure

Local structural patterns like $\alpha$-helices and $\beta$-pleated sheets, stabilized by hydrogen bonds between amino acids.

$\phi$ (Phi)

The angle of rotation around the N-C bond in a polypeptide backbone.

$\psi$ (Psi)

The angle of rotation around the C-C bond in a polypeptide backbone.

Tertiary Structure

The overall three-dimensional folding of a single polypeptide chain.

Quaternary Structure

The functional arrangement of multiple tertiary structural subunits, such as the four chains of Hemoglobin.

A-Site

The Aminoacyl site of the ribosome where the tRNA with an attached amino acid first binds.

P-Site

The Peptidyl site of the ribosome where the growing polypeptide chain is held.

E-Site

The Exit site where empty tRNAs leave the ribosome.

AlphaFold

An artificial intelligence model developed by DeepMind that has predicted over 200 million protein structures.

Heat Shock Proteins (HSPs)

Chaperones that stabilize unfolded proteins and prevent aggregation, often upregulated during cellular stress like high temperature.

Chaperonin

A protein complex consisting of a hollow cylinder and a cap that creates a hydrophilic environment to facilitate proper protein folding.

$$PrP^c$$

The normal, non-pathogenic cellular configuration of the prion protein.

$$PrP^{sc}$$

The abnormal, transmissible, and pathogenic conformation of the prion protein (named after 'scrapie').

TSEs

Transmissible Spongiform Encephalopathies, the histological and MRI findings characteristic of prion diseases.

Kuru

A human prion disease known to be transmitted through human-to-human contact.

Onpattro

An RNA interference (siRNA) therapy for hereditary transthyretin-mediated (hATTR) amyloidosis that cleaves TTR mRNA to decrease amyloid deposition.