Bio Microbiology - Spring 2012 Learning Guide 03.

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Bio 230 - Microbiology - Spring 2012 Learning Guide 03

1 Bio Microbiology - Spring 2012 Learning Guide 03

3 Walsby's Square Bacteria

4 Images of cells from 12 different colonies on blood agar plates. All are with phase-contrast optics, at standard x1000 magnification.

6 Science 27 November 2009: Vol pp DOI: /science Why and How Bacteria Localize Proteins L. Shapiro, H. H. McAdams,1 R. Losick Despite their small size, bacteria have a remarkably intricate internal organization. Bacteria deploy proteins and protein complexes to particular locations and do so in a dynamic manner in lockstep with the organized deployment of their chromosome. The dynamic subcellular localization of protein complexes is an integral feature of regulatory processes of bacterial cells.

7 Localization patterns. (A) An anterior-posterior cellular localization axis is exhibited by the Caulobacter histidine kinases PleC (red) and DivJ (green) that dynamically and selectively localize to specific cell poles. The ZapA cell division protein (blue) localizes to the FtsZ ring. (B) In these same cells, a dorsal-ventral localization axis is exhibited by crescentin (cres) intermediate filaments that localize along the inner concave side of the crescent-shaped cell and are responsible for this distinctive cell shape ; in contrast, the chemotaxis sensor array localizes at the convex outer side of the crescent near the cell pole. DAPI, 4',6-diamidino-2-phenylindole.

10 WHY? Variation of lipid composition (fatty acids (18:1 and 16:0) and phospholipid headgroups (PG, PI and CL)) of the Corynebacterium glutamicum plasma membrane in response to temperature variation during growth.

Entry of Cationic Proteins http://www.scq.ubc.

11 Entry of Cationic Proteins

12 Schematic representation of transmembrane proteins: 1. a single transmembrane α-helix (bitopic membrane protein) 2. a polytopic α-helical protein 3. a transmembrane β barrel The membrane is represented in light brown.

Succinate dehydrogenase or succinate-coenzyme Q reductase (SQR) or Complex II is an enzyme complex, bound to the inner mitochondrial membrane of mammalian mitochondria and many bacterial cells.

13 Succinate dehydrogenase or succinate-coenzyme Q reductase (SQR) or Complex II is an enzyme complex, bound to the inner mitochondrial membrane of mammalian mitochondria and many bacterial cells. It is the only enzyme that participates in both the citric acid cycle and the electron transport chain. In step 8 of the citric acid cycle, SQR catalyzes the oxidation of succinate to fumarate with the reduction of ubiquinone to ubiquinol. This occurs in the inner mitochondrial membrane by coupling the two reactions together.

16 6 transmembrane subunits C - Tilt: 22 - Segments: 1(25-49), 2(68-93), 3( ) D - Tilt: 25 - Segments: 1(17-39), 2(55-80), 3(88-113) E - Tilt: 25 - Segments: 1(17-39), 2(55-80), 3(88-113) G - Tilt: 22 - Segments: 1(25-49), 2(68-93), 3( ) J - Tilt: 25 - Segments: 1(17-39), 2(55-80), 3(88-113) L - Tilt: 22 - Segments: 1(25-49), 2(68-93), 3( )

(1) The E. coli OmpA protein (8 β strands), which serves as a receptor for a bacterial virus. (2) The E. coli OMPLA protein (12 β strands), is a lipase that hydrolyses lipid molecules.

19 (1) The E. coli OmpA protein (8 β strands), which serves as a receptor for a bacterial virus. (2) The E. coli OMPLA protein (12 β strands), is a lipase that hydrolyses lipid molecules. The amino acids that catalyze the enzymatic reaction (shown in red) protrude from the outside surface of the barrel. (3) A porin from the bacterium Rhodobacter capsulatus, which forms water-filled pores across the outer membrane (16 β strands). The diameter of the channel is restricted by loops (shown in blue) that protrude into the channel. (4) The E. coli FepA protein (22 β strands), which transports iron ions. The inside of the barrel is completely filled by a globular protein domain (shown in blue) that contains an iron-binding site.

20 Bacterial protein secretion through the translocase nanomachine E. Papanikou, S. Karamanou & A. Economou Nature Reviews Microbiology 5, (November 2007)

Peter Dennis Mitchell, FRS (29 September 1920 10 April 1992) was a British biochemist who was

21 Peter Dennis Mitchell, FRS (29 September April 1992) was a British biochemist who was awarded the 1978 Nobel Prize for Chemistry for his discovery of the chemiosmotic mechanism of ATP synthesis.

24 Binding proteins involved with the transport of maltodextrins and mercury, for proton transport a bacteriorhodopsin and components of the glucose PTS from E. coli.

28 The final synthesis of the bacterial cell wall takes place outside of the cell membrane, a place where energy is not available. A transpeptidation reaction drives the linking of new peptidoglycan to old peptidoglycan.

30 Penicillin works by interfering with transpeptidation which is essential for peptidoglycan cross-linking

33 Lysozyme works by breaking the -1,4 linkage between NAM and NAG in peptidoglycan

34 Lysozyme digests bacterial cell walls, and is found in human tears, egg-white, etc. glutamate35 and aspartate52 are involved in catalysis: note how far apart they are in the 1 structure.

40 The End

Chapter 14 - Electron Transport and Oxidative Phosphorylation

Chapter 14 - Electron Transport and Oxidative Phosphorylation The cheetah, whose capacity for aerobic metabolism makes it one of the fastest animals Prentice Hall c2002 Chapter 14 1 14.4 Oxidative Phosphorylation