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Transcript of BCHS 6229 Protein Structure and notes/BCHS6229-12-11-note.pdf · PDF file BCHS 6229...

  • 1

    BCHS 6229

    Protein Structure and FunctionProtein Structure and Function

    Lecture 12 (Nov 17, 2011)

    Special topics II (project papers # 2, 4, 6, & 9)

  • 2

    Paper # 2

  • 3

    Cataract: the most common cause of blindness - of enormous

    medical (and economical) relevance worldwide.

    Many causes:

    - mutation in one of the lenticular proteins (usually already

    present at birth);

    - one of the symptoms of systemic disease, for example

    diabetes is a risk factor for cataract;

    - the result of mere ageing.

  • 4

    Lenticular proteins, such as the abundant water-soluble

    proteins, the crystallins, cannot be replaced and thus have to

    last the lifetime of the organism.

    Crystallins in mammals: A, and B;

    B1, B2, B3, A3/A1, A2, and A4;

    A, B, C, D, E, F, and S),

  • 5Fig. Sequence alignment of the -crystallin family.

  • 6

    Structure of crystallins and their relatives: two families

    Structure of a plant small heat shock protein assembly

    1.The -crystallins

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    2. Structure of the two-domain - and -crystallins

    The domain is an independent fold

    The modular structure of the

    crystallins. (a) Each -crystallin

    domain is made from two linear

    sequence related Greek key

    motifs that intercalate on folding to form two -sheets.

  • 8

    Structural polydispersity in the lens crystallins. The lens -

    crystallins constitute an array of differently sized proteins. Although the -crystallin family members are individually

    monodisperse, the oligomeric crystallins have the potential of

    greater polydispersity.

  • 9

    Paper # 4

  • 10

    Paper # 3

    CAZy ~ Carbohydrate-Active enZymes

    Glycosyltransferases:Structures, Functions, and Mechanisms

    Lairson et al.,

    (http://www.cazy.org).

    Sugar nucleotide-dependent GT

  • 11

    Currently 94 families

  • 12

  • 13

    Paper # 6

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    Photoreceptor protein families. Six distinct types of photoreceptors

    (chromophore). Photoactivation triggers a

    characteristic series of events unique to each of

    the six photosensory protein types, and can be

    based on initial photochemical events involving

    C=C double bond photoisomerization, electron

    transfer or the formation of a chemically reactive

    triplet state. Light induces conformational

    changes in the photoreceptor domain that are

    transduced to a downstream output domain,

    which can either be fused to the photoreceptor

    in the same protein, or be represented by a

    separate protein.

  • 15

    Paper # 9

    peptidoglycan hydrolase AmiE