BIOB11H3 Lecture Notes - Lecture 4: Thiamine, Meiosis, Coenzyme A

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ceruleanweasel185

17 Mar 2012

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3rd picture: mutation in gene encoding protein involvedin making vitamin pantothenic acid. If enzyme #2 gene mutated, the providing cells w/ c will rescue", but roviding a and b will not. Eukaryotic transcription steps: 51 to 31 (strand being synthesized, unwinnding dna = topological stress, supercoiling alleviates torsional stress, ntp ydrolysis provides energy, many polymerases can act simultaneously. Random initiation sites initiation occurs at proper sites. Arrangments of elements in bacterial promotor consensus sequences ocated @-35 and -10 in prokaryotic genes. 3 different eukaryotic rna polymerases can be distinguished by their susceptibility to alpha-amanitin. Nucleolus: clusters; of rrna genes and site of ribosome assembly. Many eukaryotes: rrna gene clusters (nor) exist as tandem repeats on several x-somes. Rna size can be estimated based on sedimentation of molecule during centrigation. S/svedberg value: correlated with size and shape, so larger s value means that the molecule is larger (with perhaps a greater sa) than one have a lower s value.

Related Questions

Match each of the following with one or more answers from the list below. Some answers may not be used.

Fuel used preferentially by heart muscle and during starvation ______

Metabolic pathway that requires NADPH and malonyl-CoA ______

Cofactor used as a carrier of activated CO2 ______

Enzyme using above carrier that is inactivated by avidin ______

Derivatives of cholesterol which act as detergents to emulsify lipids ______

Metabolic pathway discovered by Franz Knoop ______

Protein involved in fatty acid synthase that has a covalent pantothenic acid attached to it ______

A thromboxane that causes platelets to aggregate ______

An inhibitor of photosystem II ______

The enzyme responsible for fixing CO2 in plants ______

Disease in children due to vitamin D deficiency ______

Drug used to lower blood cholesterol level ______

Uncoupler of Oxidative phosphorylation used as diet drug in 1920âs ______

A. NADPH Z. DNP L. Rubisco

B. bile salts G. biotin M. atrazine

C. FA synthesis H. lovastatin N. TXA₂

D. b-oxidation I. osteomalacia O. androgens

E. ketone bodies J. cytochrome P450 P. 21-hydroxylase deficiency

F. pyruvate carboxylase K. rickets Q. acyl carrier protein

viridianporcupine200

Question 3 (8 points)

Consider the following mutations and, for each, explainwhether

a) you expect it to be potentially promotingcancer AND

b) you expect it to be a dominant or recessivemutation.

i) A mutation that destroys the active site ofan enzyme necessary to promote cell cycle

ii) A very premature STOP codon in a geneencoding a protein involved in the excision-repair mechanism

iii) A point mutation that rendersconstitutively active one of the signaling proteins in the Raspathway

iv) A null mutation in a gene encoding anapoptotic (apoptosis-promoting) protein

amethystgnat217

Pantothenic acid (vitamin B5 ) is the substrate for the biosynthesis of coenzyme A, an essential cofactor in energy metabolism. Because mammals obtain vitamin B5 from their diet, the biosynthesis of pantothenic acid in pathogenic bacteria has been identified as a drug target. Ketopantoate reductase (KPR) catalyzes the NADPH-dependent reduction of ketopantoate (KP) to pantoate, the essential precursor of pantothenic acid. Previous structural and kinetic studies have focused on Escherichia coli KPR, a monomeric enzyme with globular N- and C-terminal domains. The N terminal domain of E. coli KPR contains a Rossmann fold for binding NADPH. KP binds in the active site that is formed in the interface between the domains. The catalytic reaction follows a sequential ordered bi-bi kinetic mechanism in which the enzyme binds NADPH first, followed by KP for the hydride transfer. Here we report the structural and kinetic analysis of KPR from Staphylococcus aureus, an important human pathogen. Unlike the E. coli enzyme, S. aureus KPR forms a stable, dimeric complex that is highly conserved among several deeply divergent KPRs. Steady state analysis of the S. aureus enzyme also displays positive cooperativity with respect to the cofactor. We present evidence that the cooperativity is best explained by a random addition mechanism with a kinetically preferred path. Thus, the mechanism of S. aureus KPR is distinct from those of previously described members of the family of 2-hydroxyacid dehydrogenases.

(I always have trouble reading and comprehending scientific articles) What's the motivation for the investigation? How is the author's motivation for performing the investigation related to other work in the field?

BIOB11H3 Lecture Notes - Lecture 4: Thiamine, Meiosis, Coenzyme A

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