BIOL2200 Lecture Notes - Lecture 9: Groes, Atp Hydrolysis, Methylation
CELL MACHINERY LEC 1 BIOL2200
Lecture 1: introduction to cellular machinery
1. Assembly
2. Function
3. Regulation
4. Biology
1. Assembly of cellular machinery
Proteins - cells functional units does all the work in a cell
oProtein sequences encoded by genes (DNA storage)
oTranslated from mRNA exported from nucleus
oTranscriptional and translational complexes are examples of cellular machines
Structure of a protein
oStructural motifs are combinations of secondary structures
oDetermined by primary sequence made up of aa's
oFolding aided by chaperones (another example of cell machinery)
oDimerization/oligomerisation gives rise to quaternary structures
Tertiary vs quaternary structure
oDomains are distinct regions of tertiary protein structure parts of a larger course
oLarger than structural motifs, in addition to structural properties they can also be
functional (i.e. Enzymatic/catalytic activity)
oProteins are modular in this way
oNote this slide depicts a homo-trimer. Different proteins can also come together in
quaternary structures (i.e. heteromers)
Units used in measure of protein size/mass
oDalton: standard unit used to measure mass at molecular or atomic scale (1 Da =
~1.7x10^-27 kg)
oProtein generally measured in kilodaltons (kDa)
oProtein complexes or machines in the megadaltons (Mda)
oSvedberg unit (Sv or S): rate (velocity) of sedimentation on a centrifuge
(sedimentation co-efficient)
oRelated to size, shape and density of the particle the bigger it is, the faster it
sediment… also the shape contributes… so its not a standard unit of measure. So 50s is
NOT double 25s, while 50Da IS double 25Da
oBigger it is, the faster it sediments under high g-force and thus greater svedberg unit
oNon-standard, non-linear unit of measurement
Quaternary vs macromolecular complex
oComprising multiple protein components (subunits)
oTypically very large. Many examples >1 megadalton (Mga). Typical protein ~70
kilodaltons (kDa)
o30-300nm and visible under electron microscopy
oMother natures nanot-acines
Bonsai - an 10 protein subunit outer kinetochore complex required for
microtubule attachment
Assembly of macromolecular complexes
oDiverse modes of assembly
oAssembly around a core subunit/complex
1. Function: how do cellular machines work?
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Proteins - cells functional units does all the work in a cell. Transcriptional and translational complexes are examples of cellular machines. Structural motifs are combinations of secondary structures: determined by primary sequence made up of aa"s o. Folding aided by chaperones (another example of cell machinery: dimerization/oligomerisation gives rise to quaternary structures. Tertiary vs quaternary structure: domains are distinct regions of tertiary protein structure parts of a larger course. Larger than structural motifs, in addition to structural properties they can also be o functional (i. e. enzymatic/catalytic activity) o. Proteins are modular in this way: note this slide depicts a homo-trimer. Different proteins can also come together in quaternary structures (i. e. heteromers) Units used in measure of protein size/mass: dalton: standard unit used to measure mass at molecular or atomic scale (1 da = Protein complexes or machines in the megadaltons (mda) Svedberg unit (sv or s): rate (velocity) of sedimentation on a centrifuge (sedimentation co-efficient) o.
