{{Infobox protein family | Symbol = NHL | Name = NHL repeat | image = PDB 1q7f EBI.jpg | width = | caption = Structure of the brain tumor-Pumilio translation repressor complex.<ref name="pmid14561773">{{cite journal |vauthors=Edwards TA, Wilkinson BD, Wharton RP, Aggarwal AK |title=Model of the brain tumor-Pumilio translation repressor complex |journal=Genes Dev. |volume=17 |issue=20 |pages=2508–2513 |date=October 2003 |pmid=14561773 |pmc=218144 |doi=10.1101/gad.1119403 }}</ref> | Pfam = PF01436 | Pfam_clan = CL0186 | InterPro = IPR001258 | SMART = | PROSITE = | SCOP = 1q7f | TCDB = | OPM family = | OPM protein = | CDD=cd05819 | PDB = {{PDB2|1q7f}} , {{PDB2|1rwi}} , {{PDB2|1rwl}} }}

The '''NHL repeat''', named after ncl-1, HT2A and lin-41, is an amino acid sequence found largely in a large number of eukaryotic and prokaryotic proteins. For example, the repeat is found in a variety of enzymes of the copper type II, ascorbate-dependent monooxygenase family which catalyse the C-terminus alpha-amidation of biological peptides.<ref name="pmid18632609">{{cite journal |vauthors=Kano S, Miyajima N, Fukuda S, Hatakeyama S | title = Tripartite motif protein 32 facilitates cell growth and migration via degradation of Abl-interactor 2 | journal = Cancer Res. | volume = 68 | issue = 14 | pages = 5572–5580 |date=July 2008 | pmid = 18632609 | doi = 10.1158/0008-5472.CAN-07-6231 | doi-access = free }}</ref> In many it occurs in tandem arrays, for example in the RING finger beta-box, coiled-coil (RBCC) eukaryotic growth regulators.<ref name="pmid9868369">{{cite journal |vauthors=Slack FJ, Ruvkun G | title = A novel repeat domain that is often associated with RING finger and B-box motifs | journal = Trends Biochem. Sci. | volume = 23 | issue = 12 | pages = 474–5 |date=December 1998 | pmid = 9868369 | doi = 10.1016/S0968-0004(98)01299-7}}</ref> The arthropod 'Brain Tumor' protein (Brat; {{UniProt|Q8MQJ9}}) is one such growth regulator that contains a 6-bladed NHL-repeat beta-propeller.<ref name="pmid14561773"/><ref name="pmid11336677">{{cite journal |vauthors=Edwards TA, Pyle SE, Wharton RP, Aggarwal AK | title = Structure of Pumilio reveals similarity between RNA and peptide binding motifs | journal = Cell | volume = 105 | issue = 2 | pages = 281–9 |date=April 2001 | pmid = 11336677 | doi = 10.1016/S0092-8674(01)00318-X| s2cid = 9341061 | doi-access = free }}</ref>

The NHL repeats are also found in serine/threonine protein kinase (STPK) in diverse range of pathogenic bacteria. These STPK are transmembrane receptors with an intracellular N-terminal kinase domain and extracellular C-terminal sensor domain. In the STPK, PknD, from Mycobacterium tuberculosis, the sensor domain forms a rigid, six-bladed b-propeller composed of NHL repeats with a flexible tether to the transmembrane domain.

The NHL repeat has also been used to design a family of fully symmetrical 6-blade beta-propeller proteins called "Pizza".<ref>{{cite journal |last1=Tame |first1=Jeremy R. H. |last2=Zhang |first2=Kam Y. J. |last3=Park |first3=Sam-Yong |last4=Unzai |first4=Satoru |last5=Terada |first5=Daiki |last6=Simoncini |first6=David |last7=Addy |first7=Christine |last8=Noguchi |first8=Hiroki |last9=Voet |first9=Arnout R. D. |title=Computational design of a self-assembling symmetrical β-propeller protein |journal=Proceedings of the National Academy of Sciences |date=21 October 2014 |volume=111 |issue=42 |pages=15102–15107 |doi=10.1073/pnas.1412768111 |pmid=25288768 |language=en |issn=0027-8424|pmc=4210308 |bibcode=2014PNAS..11115102V |doi-access=free }}</ref> These proteins can also be engineered to bind mineral nanocrystals.<ref>{{cite journal |last1=Voet |first1=AR |last2=Noguchi |first2=H |last3=Addy |first3=C |last4=Zhang |first4=KY |last5=Tame |first5=JR |title=Biomineralization of a Cadmium Chloride Nanocrystal by a Designed Symmetrical Protein. |journal= Angewandte Chemie International Edition|date=17 August 2015 |volume=54 |issue=34 |pages=9857–60 |doi=10.1002/anie.201503575 |pmid=26136355}}</ref>

== References == {{Reflist}}

{{InterPro content|IPR001258}}

Category:Protein domains