biology

WD40 repeat

WD40 repeat is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand WD40 repeat rather than just read about it. In short: The WD40 repeat (also known as the WD or beta-transducin repeat) is a short structural motif of approximately 40 amino acids, often terminating in a tryptophan-aspartic acid (W-D) dipeptide. Tandem copies of these repeats typically fold together to form a type of circular solenoid protein domain called the WD40 domain.

Key takeaways

WD40 repeat belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect WD40 repeat to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of WD40 repeat from memory before moving on to harder problems.

Reference excerpt

The WD40 repeat (also known as the WD or beta-transducin repeat) is a short structural motif of approximately 40 amino acids, often terminating in a tryptophan-aspartic acid (W-D) dipeptide. Tandem copies of these repeats typically fold together to form a type of circular solenoid protein domain called the WD40 domain.

Structure WD40 domain-containing proteins have 4 to 16 repeating units, all of which are thought to form a circularised beta-propeller structure (see figure to the right). The WD40 domain is composed of about 40 to 60 amino acids with a glycine and histidine dipeptide near the N-terminus and a tryptophan and aspartic acid dipeptide most commonly at the C-terminus. Two variable regions are present. The repeats typically form a four-stranded anti-parallel beta sheet or blade. These blades come together to form a propeller with the most common being a seven-bladed beta propeller. The blades interlock so that the last beta strand of one repeat forms with the first three of the next repeat to form the 3D blade structure.

Function WD40-repeat proteins are a large family found in all eukaryotes and are implicated in a variety of functions ranging from signal transduction and transcription regulation to cell cycle control, autophagy and apoptosis. The underlying common function of all WD40-repeat proteins is coordinating multi-protein complex assemblies, where the repeating units serve as a rigid scaffold for protein interactions. The specificity of the proteins is determined by the sequences outside the repeats themselves. Examples of such complexes are G proteins (beta subunit is a beta-propeller), TAFII transcription factor, and E3 ubiquitin ligase.

Examples According to the initial analysis of the human genome WD40 repeats are the eighth largest family of proteins. In all 277 proteins were identified to contain them. Human genes encoding proteins containing this domain include:

AAAS, AAMP, AHI1, AMBRA1, APAF1, ARPC1A, ARPC1B, ATG16L1, BOP1, BRWD1, BRWD3, BTRC, BUB3, CDC20, CDC40, CDRT1, CHAF1B, CIAO1, CIRH1A, COPA, COPB2, CORO1A, CORO1B, CORO1C, CORO2A, CORO2B, CORO6, CORO7, CSTF1, DDB2, DENND3, DMWD, DMXL1, DMXL2, DNAI1, DNAI2, DNCI1, DTL, DYNC1I1, DYNC1I2, EDC4, EED, EIF3S2, ELP2, EML1, EML2, EML3, EML4, EML4-ALK, EML5, ERCC8, FBXW10, FBXW11, FBXW2, FBXW4, FBXW5, FBXW7, FBXW8, FBXW9, FZR1, GEMIN5, GNB1, GNB1L, GNB2, GNB2L1, GNB3, GNB4, GNB5, GRWD1, GTF3C2, HERC1, HIRA, HZGJ, IFT121, IFT122, IFT140, IFT172, IFT80, IQWD1, KATNB1, KIF21A, KIF21B, KM-PA-2, KEAP1, LLGL1, LLGL2, LRBA, LRRK1, LRRK2, LRWD1, LYST, MAPKBP1, MED16, MLST8, MORG1, NBEA, NBEAL1, NEDD1, NLE1, NSMAF, NUP37, NUP43, NWD1, PAAF1, PAFAH1B1, PAK1IP1, PEX7, PHIP, PIK3R4, PLAA, PLRG1, PPP2R2A, PPP2R2B, PPP2R2C, PPP2R2D, PPWD1, PREB, PRPF19, PRPF4, PWP1, PWP2, RAE1, RPTOR, RBBP4, RBBP5, RBBP7, RFWD2, RFWD3, RRP9, SCAP, SEC13, SEC31A, SEC31B, SEH1L, SHKBP1, SMU1, SPAG16, SPG, STRAP, STRN, STRN3, STRN4, STXBP5, STXBP5L, TAF5, TAF5L, TBL1X, TBL1XR1, TBL1Y, TBL2, TBL3, TEP1, THOC3, THOC6, TLE1, TLE2, TLE3, TLE4, TLE6, TRAF7, TSSC1, TULP4, TUWD12, UTP15, UTP18, WAIT1, WDF3, WDFY1, WDFY2, WDFY3, WDFY4, WDHD1, WDR1, WDR10, WDR11, WDR12, WDR13, WDR16, WDR17, WDR18, WDR19, WDR20, WDR21A, WDR21C, WDR22, WDR23, WDR24, WDR25, WDR26, WDR27, WDR3, WDR31, WDR32, WDR33, WDR34, WDR35, WDR36, WDR37, WDR38, WDR4, WDR40A, WDR40B, WDR40C, WDR41, WDR42A, WDR42B, WDR43, WDR44, WDR46, WDR47, WDR48, WDR49, WDR5, WDR51A, WDR51B, WDR52, WDR53, WDR54, WDR55, WDR57, WDR59, WDR5B, WDR6, WDR60, WDR61, WDR62, WDR63, WDR64, WDR65, WDR66, WDR67, WDR68, WDR69, WDR7, WDR70, WDR72, WDR73, WDR74, WDR75, WDR76, WDR77, WDR78, WDR79, WDR8, WDR81, WDR82, WDR85, WDR86, WDR88, WDR89, WDR90, WDR91, WDR92, WDSOF1, WDSUB1, WDTC1, WSB1, WSB2, ZFP106

See also Beta-propeller Tomosyn, a protein two WD40 domains Protein tandem repeats

References

External links Eukaryotic Linear Motif resource motif class LIG_APCC_Dbox_1 Eukaryotic Linear Motif resource motif class LIG_APCC_KENbox_2 Eukaryotic Linear Motif resource motif class LIG_COP1 Eukaryotic Linear Motif resource motif class LIG_CRL4_Cdt2_1 Eukaryotic Linear Motif resource motif class LIG_CRL4_Cdt2_2 Eukaryotic Linear Motif resource motif class LIG_EH1_1 Eukaryotic Linear Motif resource motif class LIG_GLEBS_BUB3_1 Eukaryotic Linear Motif resource motif class LIG_RAPTOR_TOS_1 Eukaryotic Linear Motif resource motif class LIG_SCF_FBW7_1 Eukaryotic Linear Motif resource motif class LIG_SCF_FBW7_2 Eukaryotic Linear Motif resource motif class LIG_SCF-TrCP1_1 Eukaryotic Linear Motif resource motif class LIG_WRPW_1 Eukaryotic Linear Motif resource motif class LIG_WRPW_2 Eukaryotic Linear Motif resource motif class TRG_ER_diArg_1 Eukaryotic Linear Motif resource motif class TRG_ER_diLys_1 Eukaryotic Linear Motif resource motif class TRG_Golgi_diPhe_1 Eukaryotic Linear Motif resource motif class TRG_PTS2

Illustrations

Worked examples

Example 1 — a first encounter with WD40 repeat

Start with the simplest possible case. Write down what WD40 repeat claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to WD40 repeat before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about WD40 repeat ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of WD40 repeat

In research: WD40 repeat appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses WD40 repeat in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: WD40 repeat is common in secondary-school and first-year university syllabi. It links to neighbouring topics Protein tandem repeats, so understanding it makes those chapters shorter.
In everyday life: Look for WD40 repeat outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study WD40 repeat in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what WD40 repeat means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain WD40 repeat out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is WD40 repeat in simple terms?

Why does WD40 repeat matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study WD40 repeat?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on WD40 repeat.