; m7 [! k2 E( W: R5 _% I- B; _ ; \: ?# b3 W9 ]6 Q- m. [; g; b封面故事：拯救北极熊仍为时不晚 # K: }3 Q( J3 bGreenhouse gas mitigation can reduce sea-ice loss and increase polar bear persistence 4 G1 s2 f5 r% z8 B) w! ihttp://www.natureasia.com/ch/nat ... 1131&issue=7326 9 ?6 f$ A+ I$ z) x( }; x4 J # a" Z# y- x' B0 ` 7 F* I: J+ ]( s胚胎中的基因网络形成（Gene networking in the embryo） " {) ]" n; `3 S7 j0 ~Emerging properties of animal gene regulatory networks ; s' N$ E' ~) N# J4 b8 vhttp://www.natureasia.com/ch/nat ... 1105&issue=7326 / M4 w. r3 N. a/ F5 i/ u2 x1 _ 7 [- C& O8 B' t" k _; i: g. k+ K# B- N8 B0 Z" b
果蝇幼虫的避光机制（How fruitfly maggots avoid sunlight）) p5 o: ?2 w7 h
Light-avoidance-mediating photoreceptors tile the Drosophila larval body wall; k# d5 K9 w) T http://www.natureasia.com/ch/nat ... 1109&issue=7326 # u$ c( u7 }- i- c2 W6 w; a( b& J, X0 i9 V
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TRIM24将组蛋白代码与乳腺癌联系起来（TRIM24 links histone code to breast cancer） ! D- L/ X1 ~% [. [- F9 _TRIM24 links a non-canonical histone signature to breast cancer # A: ^# z; F( ?http://www.natureasia.com/ch/nat ... 1113&issue=73265 i0 \) x! J, q/ f: W
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CRTC3蛋白与肥胖症有关（CRTC3 protein linked to obesity） ( ^0 C4 J8 b6 BCRTC3 links catecholamine signalling to energy balance % G1 w6 B* z$ a9 o! U! Zhttp://www.natureasia.com/ch/nat ... 1116&issue=7326 - S& `' r4 K# o- J( g+ k# S, B) `4 t( {; O3 g% |; z1 b
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附近星系中较小的恒星（The lesser lights of nearby galaxies） : E* C( s- m) X- bA substantial population of low-mass stars in luminous elliptical galaxies % r2 C( i* ^( T' K5 R t, @: c: lhttp://www.natureasia.com/ch/nat ... 1119&issue=7326 q8 Y5 x+ `& {, P" p: v8 i( ^
$ |' G. p" z% c- d- }, U# p& m' g / l# @- n0 J0 H# O* m关于土星环成因的一个新模型（The formation of Saturn’s watery rings） . B6 K2 L; \# c- n/ e$ POrigin of Saturn’s rings and inner moons by mass removal from a lost Titan-sized satellite* k, ~" Q. Z; S; D; z/ q9 y- v http://www.natureasia.com/ch/nat ... 1122&issue=7326$ _0 y! Q4 v7 @# S, I7 x
. Y; k: W5 [' z0 {% X 7 \* q0 d, K5 P一个以前不知道的缺陷类型（Pleating crystals） 4 {3 i- p8 C0 |8 vPleats in crystals on curved surfaces" u; R& y, t. R0 Y7 R http://www.natureasia.com/ch/nat ... 1125&issue=7326/ y! c. R9 D$ W
! }0 B2 w% _( W" E: _2 \/ U% n
0 ^6 w: Y5 R3 h: Z$ i地球内核磁场强度的估计（Earth’s internal magnetic field estimated） 4 c8 U: o2 K0 Z& NTidal dissipation and the strength of the Earth’s internal magnetic field0 n) N! ]# q* ?& v! [2 n http://www.natureasia.com/ch/nat ... 1128&issue=7326 / m4 @5 R/ `, ]0 S, K2 v P. w$ Z t, f& [3 ?% a
& S8 c& f! Y4 G酵母新表现型在演化过程中的引入方式（Evolutionary change fit for purpose） 0 ]0 w A8 q5 d" L+ s9 tIntercalation of a new tier of transcription regulation into an ancient circuit e, J2 h2 q; i$ s+ Q. v( y2 j http://www.natureasia.com/ch/nat ... 1134&issue=73268 D8 ^6 y0 \) X) L
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}6 {+ n/ g: `8 U9 p3 l0 y( e关于神经系统响应物理刺激的一个理论得到验证（Neural activity in the balance） . ^* _+ N: [. B% F$ g5 UNoise correlations improve response fidelity and stimulus encoding& P# }+ S1 o; o http://www.natureasia.com/ch/nat ... 1142&issue=7326. A; B( Z$ L m- |1 S6 \! Z: I- _
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黑素瘤中的抗药性机制（Drug resistance mechanism in melanoma） ; V v3 z9 d5 g1 C) b A5 MCOT drives resistance to RAF inhibition through MAP kinase pathway reactivation / Melanomas acquire resistance to B-RAF(V600E) inhibition by RTK or N-RAS upregulation $ S/ f/ C% u2 R5 Fhttp://www.natureasia.com/ch/nat ... 1094&issue=7326 # k' K& R, u, ?6 A" }& z: `/ `$ R% o. B
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RNA聚合酶的抑制（RNA polymerase inhibition） N+ N$ v$ u( r2 ^
Crystal structure of bacterial RNA polymerase bound with a transcription inhibitor protein5 U* w( a# [. z; C http://www.natureasia.com/ch/nat ... 1102&issue=7326. g# [, p% ~4 y5 S4 Q% |
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DNA转位酶的运动（DNA translocase in action）2 q# T% l3 `' a' P
Single-molecule imaging reveals mechanisms of protein disruption by a DNA translocase " ]' Z3 o8 A1 L& t7 Xhttp://www.natureasia.com/ch/nat ... 1106&issue=7326 ) m6 `* h! Q& E( {+ N& E - u8 C6 k* b$ K1 r5 V: b2 n% w% O- D* M5 e3 [1 y9 `: {4 S
离子和基质运输的耦合机制（Sodium-coupled transport） % K& B3 u2 k3 ]2 g: j/ X8 UThe mechanism of sodium and substrate release from the binding pocket of vSGLT) c" G4 G- J4 I http://www.natureasia.com/ch/nat ... 1110&issue=7326作者: lifescience1 时间: 2010-12-16 20:40
非常好 谢谢楼主作者: exin11 时间: 2010-12-17 10:30
附上原文：( f! L% i3 n4 z" V% m* Q( l
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ARTICLES 7 H2 [' K9 T$ I8 d, U----------------------' V. Q2 c9 {" X0 a6 w- P
Light-avoidance-mediating photoreceptors tile the Drosophila larval - N/ _6 g' D+ u0 ~9 s/ z5 kbody wall pp921 - 926 ' y- F- @5 q# i: F0 `Light sensing outside the eyes is common in many animals but is 3 k S* c5 W" A& ~9 o
usually confined to specialized organs. Here, the entire body wall of . P: r3 u) Y" k& G4 _the fruitfly larva is found to be tiled with blue- and ultraviolet- % p, x ^0 h! @9 alight sensing neuronal dendrites, which are essential for the larva's 4 L+ x5 s/ r" D1 sinnate light-avoidance behaviour. The phototransduction machinery used 1 K1 w% v6 D" l4 ? [1 p" iby these neurons is distinct from other Drosophila photoreceptor T- ^& N& z* o( U7 } B, wmolecules but similar to a system recently identified in nematode & h8 ]# W3 B; }1 R$ I
neurons.: a3 }( N2 x& R6 c
Yang Xiang et al.* R+ o* i0 F' M$ }4 v8 A
doi:10.1038/nature09576 6 k9 K0 L$ U2 \: OAbstract: http://www.nature.com/nature/jou ... bs/nature09576.html. D0 X, b# f$ W/ Z7 z
Article: http://www.nature.com/nature/jou ... ll/nature09576.html8 r+ `$ U# v& M! r# F0 b
& E0 R- e, N9 w' p- a9 \) KTRIM24 links a non-canonical histone signature to breast cancer pp927 ( N2 H5 k+ O$ W8 y9 w2 A- 932# e1 [% i1 l0 ?4 u7 U2 ^
A crystal structure of the tandem PHD and bromodomain regions of the & R X& l% k/ H4 D! c+ G& C
transcription and chromatin regulator TRIM24 reveals combinatorial , F# |! Y0 p) d
recognition of dual marks on the histone H3 tail. TRIM24 is involved 0 l4 t& E3 C l8 H( [6 Q0 d: R
in activation of oestrogen-dependent genes and is aberrantly expressed ( j' _/ u' b* L$ ^# jin breast cancer. # E% g! P5 V1 ?Wen-Wei Tsai et al. 4 b4 |( ]8 a3 ~+ y/ adoi:10.1038/nature09542 4 ~; z' b' \3 M$ J+ CAbstract: http://www.nature.com/nature/jou ... bs/nature09542.html* x7 \1 b" D/ ]
Article: http://www.nature.com/nature/jou ... ll/nature09542.html + R! D3 |0 J. U2 j6 @ $ R& h: R$ I7 P* ~) CCRTC3 links catecholamine signalling to energy balance pp933 - 939! {; g5 u1 X/ u# j
β-adrenergic receptor signalling in adipocytes stimulates energy & A8 V, c/ [6 P& E$ ]8 fexpenditure via cAMP-dependent increases in lipolysis and fatty-acid - F' X- {1 g" W: Y Moxidation, and this signalling mechanism is thought to be disrupted in , G$ q4 c6 D: e3 Nobesity. Here, the cAMP-responsive CREB coactivator Crtc3 is shown to % a& i1 N1 O$ u4 q0 `. z# [promote obesity in mice by attenuating β adrenergic receptor 0 [/ `1 u. g* s( ^" x
signalling in adipose tissue. M5 I5 F c, Z Z9 L7 C, wYoungsup Song et al., W# ~# ]' T9 [- A/ `# z
doi:10.1038/nature095642 D8 s! T3 E% E# O* |
Abstract: http://www.nature.com/nature/jou ... bs/nature09564.html }5 c1 i1 C6 V6 |Article: http://www.nature.com/nature/jou ... ll/nature09564.html 2 G, {7 t( R; f7 g& c/ h" Q' v" u u/ H
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LETTERS 3 @% o' A: u- a; \+ P; _----------------------( W5 H; Z/ L0 Q1 w* m
A substantial population of low-mass stars in luminous elliptical ; g) [; y8 G" L' Vgalaxies pp940 - 9420 E; s/ }, R: `6 G. L" r6 p
The stellar initial mass function describes the mass distribution of 2 N, t2 T E ?9 K$ l- ?stars at the time of their formation. This study reports observations ( p9 ~6 I+ H" y7 Z( n
of the Na I doublet and the Wing-Ford molecular FeH band in the + Y9 R2 p7 p: ~
spectra of elliptical galaxies. These lines are strong in stars with # g; {5 s# @) \$ f2 v
masses , @4 z# ?( o* ]' iPieter G. van Dokkum and Charlie Conroy & |0 I o" c8 W6 N0 x. `/ ?doi:10.1038/nature09578 " C5 u6 s- `! M: J. dAbstract: http://www.nature.com/nature/jou ... bs/nature09578.html; o9 Z5 D; y% [
Article: http://www.nature.com/nature/jou ... ll/nature09578.html . K, N. m2 h7 ]# b, a9 ] # y% ]% b6 J6 F& xOrigin of Saturn’s rings and inner moons by mass removal from a lost 7 |6 j& V2 v; p- `6 |Titan-sized satellite p943( ^% C5 \8 c: H6 z5 ]6 q
Saturn's rings are more than 90–95% water ice, which implies that 6 b+ x$ N- G) ~0 Yinitially they were almost pure ice because they are continually 5 ?6 m" [0 n7 R2 R& J0 U
polluted by rocky meteoroids. Saturn has only one large satellite, - u5 q. n* q# g
Titan, whereas Jupiter has four large satellites; additional large , U% b6 N# j& ^$ Y
satellites probably existed originally but were lost as they spiralled # e% G0 {8 Y6 W1 [0 j3 ^" ?% Jinto Saturn. Now, numerical simulations of the tidal removal of mass 7 v( `9 `$ o( c) o" q+ M. K! }8 K: q# J
from a differentiated, Titan sized satellite as it migrates inward P5 o/ r+ T" Q
towards Saturn are reported. Planetary tidal forces preferentially ; e9 n( w7 H+ s8 c; G bstrip material from the satellite's outer icy layers, while its rocky " Y4 k+ E8 {0 {" A- L2 {
core remains intact and is lost to collision with the planet. The * [$ }) u. R# i. y; bresult is a pure ice ring. q1 Q3 f+ t& e3 ?
Robin M. Canup* ?5 X% t! y) B& m7 P5 D
doi:10.1038/nature09661 " t' E% H) I/ m) n' C. _Abstract: http://www.nature.com/nature/jou ... bs/nature09661.html ( F% J5 r6 A- i/ q/ J9 J( WArticle: http://www.nature.com/nature/jou ... ll/nature09661.html, E8 L) C+ [$ s8 i) _4 j
2 C0 L4 l* q5 X' ^* G3 k
Pleats in crystals on curved surfaces pp947 - 951 ; J$ }1 Y; @+ H3 uHexagons can easily tile a flat surface, but not a curved one. Defects 7 Q7 C; X1 R8 O: t% \
with topological charge (such as heptagons and pentagons) make it + A% P! o) J0 _9 q1 h4 u; y% F5 leasier to tile curved surfaces, such as soccer balls. Here, a new type 9 ~6 i, M$ r- A( b9 ^, X) hof defect is reported that accommodates curvature in the same way as 4 |* ~! |+ ~5 y+ z/ Y' J- |" b
fabric pleats. The appearance of such defects on the negatively curved ! N6 x! X& Q& V N4 Y; }; p
surfaces of stretched colloidal crystals are observed. The results , N& [+ ~0 k' M j. S& r4 Y
will facilitate the exploration of general theories of defects in 4 _8 Q! i4 g( A
curved spaces, the engineering of curved structures and novel methods * f: n3 ~. k* Y" Yfor soft lithography and directed self-assembly. 8 o9 G; `8 o6 X* W; M7 M% W0 tWilliam T. M. Irvine, Vincenzo Vitelli and Paul M. Chaikin% Z; h" y! U6 H6 r
doi:10.1038/nature09620 - S: v1 G. m5 [$ J2 vAbstract: http://www.nature.com/nature/jou ... bs/nature09620.html + H6 x6 x/ o1 L7 KArticle: http://www.nature.com/nature/jou ... ll/nature09620.html' A8 R& S `+ e$ N% i$ q/ n, ]9 z
6 ]8 V" P! Z0 x+ c, O* u/ \$ l3 l
Tidal dissipation and the strength of the Earth’s internal magnetic 5 z2 F8 ]2 t# I U& v7 G3 ~
field pp952 - 954& v; M6 J, R" D# s7 `# n" h) P% m
Here, an indirect estimate for the magnetic field strength within the - s* F, K' w" G. `: {
Earth's core from measurements of tidal dissipation is presented. ( H8 h/ T- k7 LPreviously reported evidence of anomalous dissipation in the Earth's , B0 y3 d C0 l6 b. ?
nutations can be explained with a core-averaged field of 2.5 mT, - c$ w/ f+ {- e+ c2 x5 [0 u
eliminating the need for high fluid viscosity or a stronger magnetic : ]7 {, _% @8 n7 \+ ^field at the inner-core boundary. ! i% u9 ] P/ l! [; u' rBruce A. Buffett . L3 e2 ?3 k5 A2 wdoi:10.1038/nature09643 4 g# r$ L' b! ^' h4 vAbstract: http://www.nature.com/nature/jou ... bs/nature09643.html 6 W# e. L' i2 }. hArticle: http://www.nature.com/nature/jou ... ll/nature09643.html 1 u& q; u4 D5 d, l& O Y; x& f- I6 d4 u; e4 i3 _4 \+ @
Greenhouse gas mitigation can reduce sea-ice loss and increase polar 1 u' |# s. [) q% b) n3 Ubear persistence pp955 - 958 . o$ Y, [: K! I) jThe dramatic loss of Arctic sea ice with climate change has led to the " @' V) ~; B) o$ c. B
prediction of a tipping point beyond which ice loss is irreversible $ I! x/ z+ F) b- |3 sand polar bear habitat will be catastrophically lost. By contrast, * Z5 r6 ?% T/ O Z, E9 jthis study shows a linear relationship between temperature and sea-ice / O# |) w8 T1 i; [' q9 ocoverage that overcomes the albedo effect that would cause a tipping " V! ^; p3 l: V
point. As a result, reducing greenhouse gas emissions can have a $ L& Q2 E6 E4 j, o# \positive effect on polar bear populations. , z" r4 O: R) `7 c; T) cSteven C. Amstrup et al. , j( @# }# P8 U; ~4 k# ?9 pdoi:10.1038/nature09653- t- |8 {) \- {% Z
Abstract: http://www.nature.com/nature/jou ... bs/nature09653.html 9 @7 ^' }) m) L# v2 P6 xArticle: http://www.nature.com/nature/jou ... ll/nature09653.html. K4 i# ^5 p! h; E7 p
7 r6 h8 m# [6 H. }: O! WIntercalation of a new tier of transcription regulation into an 3 v5 t1 N Q- h8 ]ancient circuit pp959 - 963 % e% Q/ f) d1 F1 }How new phenotypes can be introduced during evolution without losses 5 \( M4 U3 U( ^
of fitness remains largely unexplained at the molecular level. By , `( s, E- R. I0 Q% g/ n3 ucomparing the molecular details of a well known process — mating type ( G, ~1 ]0 R5 }, q- R+ K' S/ _/ Hdetermination — across a large diversity of yeast species, the 4 { a) C; q: m% enetwork rewiring event of the intercalation of a new level of gene & y' h. x3 }+ I+ |5 {
transcription control into an ancient regulatory circuit is shown, # R% b/ U' B% k% L+ M1 _
which allowed for the creation of a new phenotype — taking food $ M. ]: ~+ R" Q- e. M' J- ?# i1 davailability into account when deciding to mate. v$ H/ ~8 d! z7 ULauren N. Booth, Brian B. Tuch and Alexander D. Johnson5 j; C9 R2 k& Z7 S: V- a
doi:10.1038/nature09560 ( O7 T: ~% L. [5 hAbstract: http://www.nature.com/nature/jou ... bs/nature09560.html * F" p2 ]6 x, R' GArticle: http://www.nature.com/nature/jou ... ll/nature09560.html$ m; D7 n ` d* M
6 B6 L. Z# O3 @" I& j# C5 V
Noise correlations improve response fidelity and stimulus encoding " i8 _% x& J3 lpp964 - 967/ x& M7 ^: B# k& _
This study introduces a novel recording technique for simultaneously . v z( @5 Y1 \0 b; X/ D
measuring excitatory and inhibitory conductances of retinal ganglion ! _6 J3 G' B- j% T4 [& e: Q
cells to show that excitatory and inhibitory inputs are strongly 6 d, d" ?3 N; n7 G( B! p# c% ycorrelated, thereby cancelling each other. Furthermore, dynamic clamp % Z l; h( z" c. M
is used to introduce these conductance changes into the cell with or 3 u& Q2 e7 O/ O
without correlations, and it is found that, as predicted by " I8 H# [ X0 K+ t7 i) S4 y
theoretical work, correlations significantly increase reliability of ! d6 J K# l0 |" r
the spiking response. $ i+ R+ J: }3 Q- R4 XJon Cafaro and Fred Rieke- N! \" O& @4 t$ \( {% e
doi:10.1038/nature09570 : p p. t! }4 U) j& s* HAbstract: http://www.nature.com/nature/jou ... bs/nature09570.html 9 N$ L. |+ p& U% [' a) S3 SArticle: http://www.nature.com/nature/jou ... ll/nature09570.html . t, C' g4 T6 s% r + {# ] m5 ^0 j8 d/ @3 ACOT drives resistance to RAF inhibition through MAP kinase pathway - C8 T& u {0 ^ g; {, F( ?9 Wreactivation pp968 - 972: H' y, g: Y; ]4 Z% `
Recent data from early clinical trials in melanoma patients carrying 6 ]( K' l4 f( s5 V" K! @* G' imutations in the B-RAF gene have shown promising results with the B- - O# t1 U, I8 @- r z( u3 MRAF kinase inhibitor PLX4032; however, many patients eventually 6 n- ?0 l: `8 G7 h+ p \* Y) }0 O5 ?develop resistance to this treatment. Two papers now uncover possible ! }9 h" s1 Y. jmechanisms of resistance to PLX4032. One paper shows that upregulation . ]: X- L8 U5 N' O% o/ G! a1 {
of MAP3K8 (which encodes COT) can confer resistance of melanoma cells + ^0 ?# [$ F% Yto B-RAF inhibitors, whereas another paper found that melanomas can 8 t2 G/ L% k3 [6 m
acquire resistance due to mutations of N-RAS or increased expression 8 }! Y T' L7 T: r3 l7 N. oof PDGFRβ. Each of these resistance mechanisms seems to apply to at 3 O2 z$ F/ {. O) H: P* E
least some patients on recent PLX4032 trial, whereas, surprisingly, so 7 @* C6 i1 x9 ~
far no secondary B-RAF mutations have been observed.; M" L7 o3 g7 i! r( g3 q s; q
Cory M. Johannessen et al.. j% l- @- U! k5 |
doi:10.1038/nature09627 0 p1 W) o2 ~2 [- k+ pAbstract: http://www.nature.com/nature/jou ... bs/nature09627.html s- m; o" d! }+ `8 ~
Article: http://www.nature.com/nature/jou ... ll/nature09627.html W$ _7 j; u, x) v 2 j/ S" X, L* d; H+ fMelanomas acquire resistance to B-RAF(V600E) inhibition by RTK or N- 0 x9 l) y- s M/ |/ O% kRAS upregulation pp973 - 977 5 L2 F& b3 P- v( T0 H) GRecent data from early clinical trials in melanoma patients carrying 8 D& y9 Q }: }- {' t5 s5 a
mutations in the B-RAF gene have shown promising results with the B- $ E. R, g& q; ^+ V
RAF kinase inhibitor PLX4032; however, many patients eventually ( p) E. _: f( ?( r
develop resistance to this treatment. Two papers now uncover possible 4 @ \$ g) v# P6 R) l/ G& e. r" lmechanisms of resistance to PLX4032. One paper shows that upregulation ; [% O" ^+ s2 Z* d- G& l- ?of MAP3K8 (which encodes COT) can confer resistance of melanoma cells 8 A8 H8 H. _ b5 c0 n& {6 _
to B-RAF inhibitors, whereas another paper found that melanomas can 1 P5 } N7 v# }% N& D+ l1 D& yacquire resistance due to mutations of N-RAS or increased expression 9 `" ?# q6 n" M9 i# Y% E1 gof PDGFRβ. Each of these resistance mechanisms seems to apply to at : _) K& E: x2 u. ^3 s/ X! l) i3 ^least some patients on recent PLX4032 trial, whereas, surprisingly, so % i, c& p; [- l( Qfar no secondary B-RAF mutations have been observed. . u* L3 B$ Q4 aRamin Nazarian et al.; \2 Z% A x- d" e( e# `" w
doi:10.1038/nature09626 " a2 |: S- E* h1 R6 N, jAbstract: http://www.nature.com/nature/jou ... bs/nature09626.html & L1 p* S& O# T$ zArticle: http://www.nature.com/nature/jou ... ll/nature09626.html 0 W @, Z, F: z! v, O; M7 d" K% v# T. H/ X F- ^4 A/ c* z7 b
Crystal structure of bacterial RNA polymerase bound with a 2 t3 I) m$ ?# `' w( p" d5 d' A; i
transcription inhibitor protein pp978 - 982 ' b$ m* @6 `/ i; S8 t ~A crystal structure of bacterial RNA polymerase (RNAP) bound to the 2 S& P/ J- @& V: u' `( S% Z1 t
transcription inhibitor Gfh1 reveals the mechanism of inhibition by 6 e4 B3 O6 a' B9 \
Gfh1 and an alternative ratcheted state of RNAP.- L" U3 c, U( a9 T
Shunsuke Tagami et al. % o; c$ |9 s$ e4 Wdoi:10.1038/nature09573 . ?1 r2 f* W1 PAbstract: http://www.nature.com/nature/jou ... bs/nature09573.html 5 g/ B; S7 @$ E' V, q; l# s8 w7 lArticle: http://www.nature.com/nature/jou ... ll/nature09573.html - B* N9 C( m7 b" q+ l t! u# E( l. h ) M% O# g' r7 c% Z: z$ F( |* I' PSingle-molecule imaging reveals mechanisms of protein disruption by a 6 M2 U d: Y& l) w8 NDNA translocase pp983 - 987 * j8 t& }, I5 `/ r6 o V8 dProtein machineries that move along the DNA, such as DNA polymerases 7 o( J; t4 b2 M6 c* R: J6 R/ @and helicases, will necessarily encounter other bound proteins & l q+ j1 |8 r
interacting with specific sites. Using 'curtains' of labelled DNA, $ J: N/ ^; m4 }this study measured whether such bound proteins interfere with the 0 I/ c3 s' @% U9 x
activity of the bacterial DNA translocase RecBCD. The translocase is 5 a4 n/ _' g8 v# r8 d1 v( zable to push the proteins over nonspecific sites for thousands of base 0 ^, C: J, T, r, W+ j" j
pairs before they are displaced.( \) O/ c* Y! j
Ilya J. Finkelstein, Mari-Liis Visnapuu and Eric C. Greene% D4 K* x$ c* H/ u8 r/ b/ ^1 y
doi:10.1038/nature09561 & O% Z- c& L! y3 @: |9 RAbstract: http://www.nature.com/nature/jou ... bs/nature09561.html+ V; s1 M( [1 q! |3 u7 V; V. L4 ]
Article: http://www.nature.com/nature/jou ... ll/nature09561.html+ a6 O# [# {* u) j
; v7 i* H& ^% }8 k. p
The mechanism of sodium and substrate release from the binding pocket 3 I! B# q6 J' {% E
of vSGLT pp988 - 991, O3 g% ]( ]+ R- z
Here, a comprehensive study of the sodium/galactose transporter # T3 M6 i0 {, m6 E# s(vSGLT) is presented, consisting of molecular dynamics simulations, / d1 n) A/ l7 @7 o1 i/ vbiochemical characterization and a new crystal structure of the ( ~, J e, ?2 @6 H& z'inward-open' conformation. These experiments show that sodium exit 1 f/ K" V: H6 o% `/ j" C1 h# W7 _' R
causes a reorientation of transmembrane helix 1, opening an inner gate 4 N L6 J2 L: ?9 Z
required for substrate exit, while also triggering minor rigid-body ' g! C$ L; Z" l
movements in two sets of transmembrane helical bundles. This cascade ; d; O, _; r [# a' d8 _# o- @of conformational changes is responsible for the proper timing of ion 5 \: s9 D3 n. [$ `+ Rand substrate release.
非常好 谢谢楼主