CH369_lecture5_2-3-2009

CH369_lecture5_2-3-2009 - Motor proteins Lessons from...

Info iconThis preview shows pages 1–17. Sign up to view the full content.

View Full Document Right Arrow Icon
Motor proteins
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Lessons from biological system Spider silk, made of a protein called fibroin, consists of Ala- and Gly-rich β sheets interspersed with more amorphous segments of polypeptide.
Background image of page 2
Cell migration and metastasis Normal functions Wound healing Fighting infection Pathological -metastasis Crawling
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
What happens during muscle contraction? Do muscle cells become shorter? What is the energy source?
Background image of page 4
Cytoskeleton Cytoskeleton –Molecules serve the functions to a cell much like skeletal systems to the body The cytoskeleton accounts for the majority of a cell’s mass provides the cell with rigidity and shape , much like the skeletal system of the body. Unlike the animal skeletal system, the components of the cytoskeleton are ever- changing.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Globular proteins. They are responsible for carrying out the bulk of the metabolic reactions of cells: harvesting and storing free energy, transforming biological compounds into others, decoding genetic information. Fibrous proteins They are elongated and often insoluble, abundant. These proteins determine the shape and other physical attributes of cells and organisms.
Background image of page 6
Microfilament A major portion of the eukaryotic cytoskeleton consists of microfilaments, or polymers of actin. In many cells, a network of microfilaments supports the plasma membrane and therefore determines cell shape
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Structure of actin Electron X-ray Modeled micrograph crystal based on structure x-ray crystal structure
Background image of page 8
Actin F-actin (for filamentous actin) - Polymerized actin G-actin, the globular monomeric form
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Actin assembly - Most of the actin subunits in a microfilament contain bound ADP - The presence of ATP to actin is not essential for polymerization
Background image of page 10
Actin Hydrolyzes ATP and binds to both ATP and ADP
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Microfilaments are dynamic structures Dissociation polymerization Treadmilling: rate of dissociation = polymerization
Background image of page 12
Capping stops polymerization In vivo, the rate of polymerization > dissociation
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Cell migration Crawling Extracellular signals, regulate the assembly and disassembly of Microfilaments.
Background image of page 14
Myosin : A motor protein associated with actin A skeleton muscle fiber
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Myosin is composed of a homodimer Coiled-coil
Background image of page 16
Image of page 17
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 62

CH369_lecture5_2-3-2009 - Motor proteins Lessons from...

This preview shows document pages 1 - 17. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online