Lipases and the enolase superfamily (Lec5)

Question 1

Describe the AS of lipases

Answer 1

Has a catalytic triad of Ser,His,Asp

Question 2

Describe a lipase inhibitor of pancreatic lipase

Answer 2

Lipstatin - B lactone ring of a lipstatin binds to Ser in AS after the capping complex has revealed AS following interaction w/ colipase

Question 3

Describe the immunity protein of Burkholderia and the reasons for its production

Answer 3

Burkholderia TVI secretion system secretes lipase into other cells for hydrolysis lipase cant break down cellular components therefore immunity protein binds so that lipase not active in bacterial cell immunity protein (in Burkholderia) binds to the capping complex and prevents its collapse on AS therefore AS not revealed

Question 4

Give an example of a member of the enolase superfamily

Answer 4

Mandelate racemase , enolase

Question 5

Draw a rough diagram of the enolase superfamily enzymes & state where the acid base chemistry occurs

Answer 5

Question 6

Do enzymes of the enolase superfamily have a capping domain?

Answer 6

yes - interface of the capping domain and barrel domain = substrate binding

Question 7

Is there any similarity between members of the enolase superfamily? (mandelate racesmase, enolase)

Answer 7

No sequence similarity - not surprised because v different mechanisms Some structural similarity - especially around the AS, and residues coordinating the Mg2+ ion (eg Glu and Asp) are spatially conserved

Question 8

What is the main metal ion found in the enolase superfamily?

Also state how it is coordinated in the AS

Answer 8

Mg2+

Asp and Glu residues

Question 9

Draw the product that occurs from the mandelate racesmase enzyme of this compound

Answer 9

Question 10

What type of secretion system allows Burkholderia secrete lipases?

Answer 10

Type VI