Sandbox Reserved 770: Difference between revisions
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Phenylalanine ammonia lyase enzyme is a dimer composed of two identical subunits. <ref name="crystallization">http://ci.nii.ac.jp/els/110006324658.pdf?id=ART0008332067&type=pdf&lang=en&host=cinii&order_no=&ppv_type=0&lang_sw=&no=1386328093&cp=</ref> Each subunit of PAL from ''R. toruloides'' assume a "seahorse" shape by interlocking head-to-tail, creating overlapping regions with two adjacent subunits, as shown by Figure 2. These overlapping regions maximize interactions between subunits, giving rise to the formation of the tightly assembled tetramer, as shown in Figure 3. Formation of the tetramer buries 58% of their combined surfaces. <ref name=crystal>http://pubs.acs.org.prox.lib.ncsu.edu/doi/pdfplus/10.1021/bi049053%2B</ref> Of the 66 interactions between adjacent subunits, 25 hydrogen bonding interactions exists between Asp & Glu carboxylate oxygens and NH2 & OH moieties, including a prominent band of Asp & Glu interactions with Arg side chains between subunits nearby the central bundle of helices. PAL's central core is comprised of parallel alpha helices of varying lengths. There is only one section of Beta sheet longer than three residues in PAL, which resides in the funnel region leading to the active site. PAL and HAL (Histadine Ammonia Lyase) contain similar folds, but PAL differs from HAL with 215 additional residues. Of the 215 residues from this section, 155 residues extend above and below the main body of the structure, creating a "fan" arrangement, shown as the bracketed areas in Figure 3a. | Phenylalanine ammonia lyase enzyme is a dimer composed of two identical subunits. <ref name="crystallization">http://ci.nii.ac.jp/els/110006324658.pdf?id=ART0008332067&type=pdf&lang=en&host=cinii&order_no=&ppv_type=0&lang_sw=&no=1386328093&cp=</ref> Each subunit of PAL from ''R. toruloides'' assume a "seahorse" shape by interlocking head-to-tail, creating overlapping regions with two adjacent subunits, as shown by Figure 2. These overlapping regions maximize interactions between subunits, giving rise to the formation of the tightly assembled tetramer, as shown in Figure 3. Formation of the tetramer buries 58% of their combined surfaces. <ref name=crystal>http://pubs.acs.org.prox.lib.ncsu.edu/doi/pdfplus/10.1021/bi049053%2B</ref> Of the 66 interactions between adjacent subunits, 25 hydrogen bonding interactions exists between Asp & Glu carboxylate oxygens and NH2 & OH moieties, including a prominent band of Asp & Glu interactions with Arg side chains between subunits nearby the central bundle of helices. PAL's central core is comprised of parallel alpha helices of varying lengths. There is only one section of Beta sheet longer than three residues in PAL, which resides in the funnel region leading to the active site. PAL and HAL (Histadine Ammonia Lyase) contain similar folds, but PAL differs from HAL with 215 additional residues. Of the 215 residues from this section, 155 residues extend above and below the main body of the structure, creating a "fan" arrangement, shown as the bracketed areas in Figure 3a. | ||
==Central Core and MIO Cofactor== | ==Central Core and MIO Cofactor== | ||
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[[Image:Positive_Negative_Helices_PAL.png|thumb|left|Figure 6. Six positive poles toward the active site, one negative pole toward the active site]] | [[Image:Positive_Negative_Helices_PAL.png|thumb|left|Figure 6. Six positive poles toward the active site, one negative pole toward the active site]] | ||
==Active Sites== | ==Active Sites== | ||
