Proteins Tertiary Protein Structure of Enzyme Lactasevideo Video 2

Fig. 5-21d Abdominal glands of the spider secrete silk fibers made of a structural protein containing  pleated sheets. The radiating strands, made of dry silk fibers, maintain the shape of the web. The spiral strands (capture strands) are elastic, stretching in response to wind, rain, and the touch of insects.

Table 5.1 An Overview of Protein Functions

Examples of Protein Functions in Cell  Link to Enzymes Link to Enzymes Link to Enzymes  Link to Structural Proteins Link to Structural Proteins Link to Structural Proteins  Link to Contractile Proteins Link to Contractile Proteins Link to Contractile Proteins  Link to Gene Regulation Proteins Link to Gene Regulation Proteins Link to Gene Regulation Proteins  Link to immune system proteins Link to immune system proteins Link to immune system proteins

Protein are polymers of amino acids; Polypeptide = chain of many amino acids

Fig. 5-UN1 Amino group Carboxyl group  carbon IB MEMORIZE LIST

In cells at neutral pH, amino acids typically exist in ionized, zwitterion form

Fig Nonpolar Glycine (Gly or G) Alanine (Ala or A) Valine (Val or V) Leucine (Leu or L) Isoleucine (Ile or I) Methionine (Met or M) Phenylalanine (Phe or F) Trypotphan (Trp or W) Proline (Pro or P) Polar Serine (Ser or S) Threonine (Thr or T) Cysteine (Cys or C) Tyrosine (Tyr or Y) Asparagine (Asn or N) Glutamine (Gln or Q) Electrically charged AcidicBasic Aspartic acid (Asp or D) Glutamic acid (Glu or E) Lysine (Lys or K) Arginine (Arg or R) Histidine (His or H)

Fig. 5-17a Nonpolar Glycine (Gly or G) Alanine (Ala or A) Valine (Val or V) Leucine (Leu or L) Isoleucine (Ile or I) Methionine (Met or M) Phenylalanine (Phe or F) Tryptophan (Trp or W) Proline (Pro or P)

Fig. 5-17b Polar Asparagine (Asn or N) Glutamine (Gln or Q) Serine (Ser or S) Threonine (Thr or T) Cysteine (Cys or C) Tyrosine (Tyr or Y)

Fig. 5-17c Acidic Arginine (Arg or R) Histidine (His or H) Aspartic acid (Asp or D) Glutamic acid (Glu or E) Lysine (Lys or K) Basic Electrically charged

Figure 5.2 The synthesis and breakdown of polymers

Figure 5.16 Making a polypeptide chain Figure 5.16 Making a polypeptide chain

Levels of Protein Structure  Primary – sequence of amino acids  Secondary- folded patterns produced by hydrogen bonding along amino-acid backbone  Tertiary- overall 3-D folding pattern produced by interactions of side-chains  Quaternary- interaction between separate amino acid chains of a protein

Figure 5.24 Review: the four levels of protein structure Figure 5.24 Review: the four levels of protein structure

Figure 5.18 The primary structure of a protein Figure 5.18 The primary structure of a protein

Figure 5.20 The secondary structure of a protein Figure 5.20 The secondary structure of a protein Link to secondary structure Localized substructures helices or sheets Linus Pauling

Arrow notation for Beta-Pleated Sheet

Interactions between R groups that contribute to tertiary structure DISULFIDE LINKAGE

Indicate for each number, the type of interaction DISULFIDE LINKAGE ION-DIPOLE HYDROGEN BOND IONIC BOND (SALT BRIDGE) LONDON DISPERSION FORCE

Fig A ribbon model of lysozyme (a)(b) A space-filling model of lysozyme Groove Link to tertiary structure animation

Fig. 5-21e Tertiary StructureQuaternary Structure

Link to Quaternary structure Link to Quaternary structure

Figure 5.23 The quaternary structure of proteins Figure 5.23 The quaternary structure of proteins Link to Quaternary structure

Fig. 5-21g FIBROUS PROTEIN – STRUCTURAL, ROPE-LIKE GLOBULAR PROTEIN - roughly spherical, water-soluble Hemoglobin Heme Iron  Chains Collagen Hemoglobin

Conformational change of hemoglobin when O 2 binds